WO2016037987A1

WO2016037987A1 - Organic compounds with a woody-peppery odour

Info

Publication number: WO2016037987A1
Application number: PCT/EP2015/070406
Authority: WO
Inventors: Philip Kraft
Original assignee: Givaudan Sa
Priority date: 2014-09-08
Filing date: 2015-09-07
Publication date: 2016-03-17
Also published as: GB201415845D0

Abstract

(Z)-Configured 5-substituted 5,6-dimethylhepta-3,6-dien-2-one possessing very characteristic dark woody odour with typical agarwood-like spicy peppery connotation.

Description

ORGANIC COMPOUNDS WITH A WOODY-PEPPERY ODOUR

The present invention relates to novel compounds possessing very characteristic dry woody-peppery odour notes of high intensity and originality. The invention furthermore refers to a method for their production, and to flavour and fragrance compositions containing these.

Agarwood, also known as oud, oodh, aloeswood, lignatoes, aioes or simply agar, is a dark resinous heartwood that forms when Aquilaria and Gyrinops trees, mainly Aquilaria agallochoa, Aquilaria malaccensis or Aquilaria sinensis, become infected with Ascomycota fungi such as Philalophora parasitica and related species. As an immune response to this attack, the trees produce a dark resin of typical dry woody-animalic, incense-like odour with a characteristic peppery spiciness and shades of amber as well as of musk. While the agarwood note has become especially trendy and sought after in perfumery in the last few years, the demand can be met neither with the very rare original material, nor with the so-called white agarwood, which is produced by artificial infections or by treatment with certain chemicals, but which does not possess the same richness and character as authentic agarwood oils. Besides, no single perfumery raw material exists to date that is able to replace authentic agarwood oil in perfumery, though there are certain materials that cover important aspects such as the dark woody-animalic tonality that can be recreated with Kephalis (A; 4- (1-ethoxyvinyl)-3,3,5,5-tetramethylcyclohexanone), woody-musky aspects that can be reproduced by Cashmeran (B; 1 ,1 ,2,3,3-pentamethyl-2,3,6,7- tetrahydro-1 H-inden-4(5H)-one), the animalic aspects, for which several aroma chemicals are available, and the ambery note, for which commercial ambergris odorants can be employed.

The most difficult part, however, is the dry woody-peppery note, which is so characteristic and still distinctly different from pepper oils. Surprisingly, it was found that certain (Z)-configured 5-substituted 5,6-dimethylhepta- 3,6-dien-2-one of formula (I) as defined herein below possess very characteristic dark woody odour reminiscent of Kephalis (A) and Cashmeran^® (B) with typical agarwood- type spicy peppery connotation.

Thus there is provided in a first embodiment the use as fragrance of a compound of formula (I) with (Z)-configured a, β-unsaturated double bond

wherein

Y is selected from phenyl, bicyclo[2.2.1]heptan-2-yl, and -CHR¹R², wherein R¹ and R² are independently selected from methyl and ethyl, or R¹ and R² form together with the carbon atom to which they are attached cyclo-C₅-C₇-alkyl (cylcopentyl, cyclohexyl, and cyctoheptyl).

The compounds of formula (I) possess at least one stereocenter at C-5 of the 5,6- dimethylhepta-3,6-dien-2-one skeleton, and optionally also further stereocenters in the substituent Y, and can be resolved into individual enantiomerically enriched or pure stereoisomers. Resolving stereoisomers however adds to the complexity of manufacture and purification of these compounds, as does a stereoselective synthetic approach, and thus it is preferred to use the compounds as mixtures of their stereoisomers simply for economic reasons. However, if it is desired to prepare individual stereoisomers, this may be achieved according to methodology known in the art, e.g. by preparative HPLC and GC or by stereoselective synthesis.

As a specific example of compounds of formula (I), one may cite (Z)-5-cyclopentyl-5,6- dimethylhepta-3,6-dien-2-one (Y = cyclopentyl), which possesses an intense dark woody odour of very low odour threshold with spicy peppery facets, and aspects of Kephalis (A) and Cashmeran (B), as well as a fruity facet in the direction of apple. As a further specific example of compounds of formula (I), one may cite (Z)-6-ethyl-5- methy!-5-(prop-1-en-2-yl)oct-3-en-2-one (Y = pent-3-yl), which possess a powerful dark woody odor reminiscence of Kephalis (A) and Cashmeran (B) with a typical agarwood- type spicy peppery connotation which is about 10 times more intense in terms of odour threshold compared with (E)-6-ethyl-5-methyl-5-(prop-1-en-2-yl)oct-3-en-2-one.

Further non-limiting examples are compounds of formula (I) selected from the group consisting of (Z)-5-cyclohexyl-5-6-dimethylhepta-3,6-dien-2-one (Y = cyclohexyl), (Z)- 5,6-dimethyl-5-phenylhepta-3,6-dien-2-one <Y = phenyl), (Z)-5-(bicyclo[2.2.1]heptan-2- yl)-5,6-dimethylhepta-3,6-dien-2-one (Y = bicyclo[2.2.1]-heptan-2-yl), and (Z)-5,6- dimethyl-5-(prop-1-en-2-yl)oct-3-en-2-one (Y = but-2-yl).

The compounds of formula (I) may be used alone, as mixtures thereof, or in combination with a base material. As used herein, the 'base material' includes all known odorant molecules selected from the extensive range of natural products, and synthetic molecules currently available, such as essential oils, alcohols, aldehydes and ketones, ethers and acetals, esters and lactones, macrocycles and heterocycles, and/or in admixture with one or more ingredients or excipients conventionally used in conjunction with odorants in fragrance compositions, for example, carrier materials, and other auxiliary agents commonly used in the art.

It was observed that under certain conditions the compounds of formula (I) are unstable over prolonged time, which may result in the formation of undesired off-odours. Surprisingly, it was found that the formation of undesired off-odours can be reduced or completely eliminated by admixing the compounds of formula (I) with an essentially odourless base, such as triethanol amine (TEOA). Thus, the compounds of formula (I) may optionally be admixed with, for example, triethanol amime in a ratio of 15:1 to 3:1 (compound of formula (I) : TEOA).

As used herein, 'fragrance composition' means any composition comprising at least one compound of formula (I) and a base material, e.g. a diluent conventionally used in conjunction with odorants, such as dipropylene glycol (DPG), isopropyl myristate (IPM), triethyl citrate (TEC) and alcohol (e.g. ethanol). Optionally, the composition may comprise an anti-oxidant adjuvant. Said anti-oxidant may be selected from Tinogard^® TT (BASF), Tinogard^® Q (BASF), Tocopherol (including its isomers, CAS 59- 02-9; 364-49-8; 18920-62-2; 121854-78-2). 2,6-bis(1 ,1-dimethylethyl)-4-methylphenol (BHT, CAS 128-37-0) and related phenols, such as hydroquinone (CAS 121-31-9).

The following list comprises examples of known odorant molecules, which may be combined with the compounds of formula (I) as herein defined:

- essential oils and extracts, e.g. agarwood oil (white and/or authentic), castoreum, costus root oil, oak moss absolute, geranium oil, tree moss absolute, basil oil, fruit oils, such as bergamot oil and mandarine oil, myrtle oil, palmarose oil, patchouli oil, petitgrain oil, jasmine oil, rose oil, sandalwood oil, wormwood oil, lavender oil or ylang-ylang oil;

alcohols, e.g. cinnamic alcohol, cis-3-hexenol, citronelloi, Ebanol™, eugenol, farnesol, geraniol, Super Muguet™, linalool, menthol, nerol, phenylethyl alcohol, rhodinol, Sandalore™. terpineol or Timberol™;

- aldehydes and ketones, e.g. Azurone^® [7-(3-methylbutyl)-1 ,5-benzodioxepin-3-one], anisaldehyde, a-amylcinnamaldehyde, Casbmeran^®, Georgywood™, Hedione^®, hydroxycitronellal, Iso E Super^®, Isoraldeine^® Kephalis™, Lilial^®, maltol, methyl cedryl ketone, methylionone, verbenone, or vanillin;

- ether and acetals, e.g. Ambrox^®. geranyl methyl ether, rose oxide, or Spirambrene^® ;

- esters and lactones, e.g. benzyl acetate, cedryl acetate, γ-decalactone, Helvetolide^®, γ-undecalactone or vetivenyl acetate;

- macrocycles, e.g. Ambrettolide, ethylene brassylate or Exaltolide^®; and

- heterocycles, e.g. isobutylchinoline.

The compounds according to formula (I) may be used in a broad range of perfumed products, e.g. in any field of fine and functional perfumery, such as perfumes, air care products, household products, laundry products, body care products and cosmetics. The compounds can be employed in widely varying amounts, depending upon the specific application and on the nature and quantity of other odorant ingredients. The proportion is typically from 0.1 to 10 weight percent of the application. In one embodiment, compounds of the present invention may be employed in a fabric softener in an amount of from 0.001 to 0.1 weight percent. In another embodiment, compounds of the present invention may be used in fine perfumery in amounts from 0.01 to 20 weight percent (e.g. up to about 10 weight percent), more preferably between 0.01 and 5 weight percent. However, these values are given only by way of example, since the experienced perfumer may also achieve effects or may create novel accords with lower or higher concentrations.

The compounds as described hereinabove may be employed in a consumer product base simply by directly mixing at least one compound of formula (I), or a fragrance composition with the consumer product base, or they may. in an earlier step, be entrapped with an entrapment material, for example, polymers, capsules, microcapsules and nanocapsules, liposomes, film formers, absorbents such as carbon or zeolites, cyclic oligosaccharides and mixtures thereof, or they may be chemically bonded to substrates, which are adapted to release the fragrance molecule upon application of an external stimulus such as light, enzyme, or the like, and then mixed with the consumer product base.

Thus, there is provided in a further aspect a method of manufacturing a perfumed product, comprising the incorporation of a compound of formula ()), as a fragrance ingredient, either by directly admixing the compound to the consumer product base or by admixing a fragrance composition comprising a compound of formula (I), which may then be mixed with a consumer product base, using conventional techniques and methods. Through the addition of an olfactory acceptable amount of at least one compound of formula (1) as hereinabove described the odour notes of a consumer product base will be improved, enhanced, or modified.

Thus, there is provided in a further aspect a method for improving, enhancing or modifying a consumer product base by means of the addition thereto of an olfactorily acceptable amount of at least one compound of formuia (I).

The invention also provides a perfumed product comprising:

a) as odorant at least one compound of formula (I); and

b) a consumer product base.

As used herein, 'consumer product base' means a composition for use as a consumer product to fulfil specific actions, such as cleaning, softening, and caring or the like. Examples of such products include fine perfumery, e.g. perfume and eau de toilette; fabric care, household products and personal care products such as laundry care detergents, rinse conditioner, personal cleansing composition, detergent for dishwasher, surface cleaner; laundry products, e.g. softener, bleach, detergent; body- care products, e.g. shampoo, shower gei; air care products and cosmetics, e.g. deodorant, vanishing creme. This list of products is given by way of illustration, and is not to be regarded as being in any way limiting.

To the best of our knowledge none of the compounds falling within the definition of formula (l) as hereinabove defined are described in the literature and are thus novel in their own right.

The compounds of formula (I) may be prepared from the respective tert-butyl ketones such as 5-( tert-butyl)-6-ethyl-5-hydroxyoct-3-yn-2-one (C), which are accessible according to P. Kraft, J. S. E. Ahlin, M. Buchel, P. Sutter, Synthesis 2012, 2985-2988, for instance by by copper(l)-catalyzed Grignard reaction of the acid chlorides with tert- butyl magnesium chloride. Lanthanum-assisted reaction of the resulting tert-butyl ketones with the bis-Grignard reacgent prepared from but-3-yn-2-ol, followed by Attenburrow oxidation of the secondary hydroxy function with manganese(IV) oxide, provide the corresponding 5-substituted 5-hydroxy-6,6-dimethylhept-3-yn-2-ones, which then are subjected to elimination/Wagner-Meerwein rearrangement conditions, for instance by stirring their dichloromethane solutions in the presence of an cation- exchange resin such as Amberlyst^® 15 (44.6 g, 100 mmol) and optionally molecular sieves 4A. The triple bond of the resulting 5-substituted 5,6-dimethylhept-6-en-3-yn-2- ones can then be completely (Z)-selectively hydrogenated employing a Lindlar catalyst to furnish all the different compounds of formula (I).

The invention is now further described with reference to the following non-limiting examples. These examples are for the purpose of illustration only, and it is understood that variations and modifications can be made by one skilled in the art.

Example 1 : (Z)-5-Cvclopentyl-5,6-dimethylhepta-3,6-dien-2-one

A solution of cyclopentanecarbonyl chloride (27.1 g, 200 mmol) and copper(l) chloride (1.00 g, 10.0 mmol, 5.0 mol%) in diethyl ether (150 mL) was stirred for 10 minutes at room temperature. At this temperature, a tert-butyl magnesium chloride solution in diethyl ether (2 M, 100 mL, 200 mmol) was added dropwise with stirring within 3.5 h, and stirring was continued for 16 h at room temperature. The reaction mixture was poured into ice/2 M aqueous hydrochloric acid (230 mL), adjusted to pH 2, and extracted with ether (2 x 250 mL). The combined organic extracts were washed with water (1 x 200 mL) and brine (1 x 200 mL), dried (Na₂SO₄), and concentrated under reduced pressure. Flash chromatography (600 g silica gel, pentane-ether, 19:1) of the resulting residue furnished 1-cyclopentyl-2,2-dimethylpropan-1-one (17.1 g, 55%) as a slightly yellowish liquid.

To a stirred solution of the lanthanum(lll)chloride bis(lithiumchtoride) complex in tetrahydrofuran (243 mL, 146 mmol, 0.6 M) was added dropwise at room temperature a solution of 1-cyclopentyl-2,2-dimethylpropan-1-one (22.5 g, 146 mmol) in tetrahydrofuran (80 mL) within 1 h, and stirring was continued for 4 h at room temperature. In a second flask, but-3-yn-2-ol (12.7 g, 175 mmol) in tetrahydrofuran (265 mL) was added dropwise within 1.5 h to a stirred so!ution of ethyl magnesium chloride in tetrahydrofuran (2 M, 175 mL, 350 mmol). The resulting reaction mixture was refluxed for 2 h, and allowed to cool to room temperature, prior to the dropwise addition to the above prepared lanthanum(lll)chlortde bis(lithiumchloride) complex/1-cyclopentyl-2,2- dimethylpropan-1-one solution within 2 h. After stirring at reflux for 16 h, the reaction mixture was poured into ice/water (500 mL), acidified with 2 M aqueous hydrochloric acid (200 mL) to pH 1 , and extracted with ether (2 χ 400 mL). The combined organic extracts were washed with water (1 x 400 mL) and brine (1 x 200 mL), dried (Na₂SO„), and concentrated under reduced pressure. Flash chromatography (1 kg silica gel, pentane-ether, 1 :1 ; R_f = 0.34) of the resulting residue afforded 5-cyc!opentyl-6,6- dimethylhept-3-yne-2,5-dioi (28.0 g, 86%) as an odourless, slightly yellowish liquid, which crystallized rapidly after short immersion in a cooling bath at -78 °C (Mp: 55.6- 58.5 °C).

A suspension of manganese dioxide (90%, 1 18 g, 1.22 mol) and 5-cyclopentyl- 6,6-dimethylhept-3-yne-2,5-diol (27.5 g, 123 mmol) in dichloromethane (450 mL) was stirred overnight at room temperature. The insoluble material was removed by filtration over a pad of Celite™, and washed thoroughly with dichloromethane. The filtrate and the washings were combined, and concentrated under reduced pressure. Flash chromatography (600 g silica gel, pentane-ether, 3:1 ; R_f = 0.47) of the resulting residue furnished 5-cyclopentyl-5-hydroxy-6,6-dimethylhept-3-yn-2-one (22.3 g, 78%) as a slightly yellowish liquid.

To a solution of 5-cyclopentyl-5-hydroxy-6,6-dimethylhept-3-yn-2-one (22.3 g, 100 mmol) in dichloromethane (220 mL) was added Amberlyst^® 15 (44.6 g, 100 mmol) and Molecular sieves 4A. The resulting reaction mixture was stirred overnight at room temperature. The insoluble material was removed by filtration over a pad of Celite™, and washed thoroughly with dichloromethane. The filtrate and the washings were combined and concentrated under reduced pressure. Purification of the resulting residue by flash chromatography (600 g silica gel, pentane-ether, 39:1 ; R_f = 0.35) provided 5-cycfopentyl-5,6-dimethylhept-6-en-3-yn-2-one (13.2 g, 64%) as a slightly yellowish oil. A solution of 5-cyclopentyl-5,6-dimethylhept-6-en-3-yn-2-one (16.1 g, 79 mmol), pyridine (310 mg, 3.94 mmol) and Lindlar catalyst (5% Pd, 490 mg) in ethanol (120 mL) was stirred under hydrogen atmosphere for 4 h. The insoluble materials were removed by filtration through a pad of Celite™ , and then thoroughly washed with ethanot. Removal of the solvent under reduced pressure in a rotatory evaporator provided the crude title compound, which was further purified by flash chromatography (1 kg silica gel, pentane-ether, 19:1 ; R_f = 0.27) and Kugelrohr distillation to afford (Z)-5- cycfopentyl-5,6-dimethylhepta-3,6-dien-2-one (9.5 g, 58%) as a colourless liquid.

Odour description: dark woody odour with spicy peppery facets, and aspects of Kephalis (A) and Cashmeran (B), as well as some fruity facets in the direction of apple.

IR (neat): 2949, 1699, 1351 , 1172, 890 cm^-1. ¹H NMR (CDCI₃): 6 = 1.18-1.38 (m, 2 H, cyclopentane ring), 1.22 (s, 3 H, CH₃), 1.47-1.67 (m, 6 H, cyclopentane ring), 1.73 (dd, J = 0.5, 1.5 Hz, 3 H, CH₃), 2.12-2.20 (m, 1 H, cyclopentane ring), 2.18 (s, 3 H, -(CO)- CH₃), 4.74 (dd, J = 0.5, 1.5 Hz, 1 H, -C=CHH), 4.77-4.78 (m, 1 H, -C=CHH), 5.87 (d, J = 13.0 Hz, 1 H, -CH=CH-), 6.05 (d, J = 13.0 Hz, 1 H, -CH=CH-).¹³C NMR (CDCI₃):

= 20.6 (q), 22.9 (q), 26.0 (t), 26.1 (t), 27.5 (t), 27.9 (t), 31.3 (q), 48.1 (s), 48.2 (d), 111.1 (t), 129.2 (d), 147.0 (d), 149.2 (s), 201.2 (s). MS: m/z (%) = 43 (100), 69 (17), 95 (95), 123 (88), 137 (55), 163 (6), 191 (2), 206 (1) [M¹].

Example 2: (Z)-5-Cyclohexyl-5-6-dimethylhepta-3,6-dien-2-one

A solution of cyclohexanecarbonyl chloride (30.2 g, 200 mmol) and copper(l) chloride (1.00 g, 10.0 mmol, 5.0 mol%) in diethyl ether (150 mL) was stirred for 10 minutes at room temperature. At this temperature, terf-butyl magnesium chloride solution in diethyl ether (2 M, 100 mL, 200 mmol) was added dropwise with stirring within 4h 45 minutes, and stirring was continued for 16 h at room temperature. The reaction mixture was poured into ice/2 M aqueous hydrochloric acid (230 mL), adjusted to pH 2, and extracted with ether (2 ·x 250 mL). The combined organic extracts were washed with water (1 x 200 mL) and brine (1 x 200 mL), dried (Na₂SO₄), and concentrated under reduced pressure to afford crude 1-cyclohexyl-2,2-dimethylpropan-1-one (33.5 g, 97%; GC-purity: 97%) as a slightly yellowish liquid, which was used in the next step without further purification.

As described in Example 1 for the synthesis of 5-cyclopentyl-6,6-dimethylhept-3- yne-2,5-diol, from a solution of lanthanum(lll)chloride bis(lithiumchtoride) complex (49.5 mL, 29.7 mmol, 0.6 M in THF), a solution of the previously prepared 1-cyclohexyl-2,2- dimethylpropan-1-one (97%, 5.0 g, 29.7 mmol) in tetrahydrofuran (15 mL), a solution of but-3-yn-2-ol (2.35 g, 32.7 mmol) in tetrahydrofuran (50 mL), and an ethyl magnesium chloride solution in tetrahydrofuran (2 M, 35.7 mL, 71.3 mmol). Standard workup and purification by flash chromatography (180 g silica gel, pentane-ether, 1:1R₁ = 0.63) of the resulting residue provided 5-cyclohexyl-6,6-dimethylhept-3-yne-2,5-diot (6.3 g, 89%) as a slightly yellowish liquid, which crystallized during standing at room temperature (Mp: 86.0 ºC - 89.5 ºC).

As described in Example 1 for the synthesis of 5-cyc!opentyl-5-hydroxy-6,6- dimethy!hept-3-yn-2-one, from 5-cyclohexyl-6,6-dimethylhept-3-yne-2,5-diol (5.3 g, 22.23 mmol) with a suspension of manganese dioxide (90%, 29 g, 334 mmol) in dichioromethane (80 mL). Filtration over a short pad of Celite™, and thorough washing of the filter cake with dichioromethane, followed by flash chromatography (120 g silica gel, pentane-ether,3: 1; R, = 0.43) of the resulting residue furnished 5-cyclohexyl-5- hydroxy-6,6-dimethylhept-3-yn-2-one (3.8 g, 72%) as a yellowish oil.

As described in Example 1 for the synthesis of 5-cyclopentyl-5,6-dimethylhept-6- en-3-yn-2-one, from 5-cyclohexyl-5-hydroxy-6,6-dimethylhept-3-yn-2-one (3.8 g, 16.08 mmol) with a stirred suspension of Amberlyst^® 15 (7.60 g, 16.1 mmol) and molecular sieves 4A (15.2 g, 16.1 mmol) in dichlormethane (40 mL). Filtration over a short pad of Celite™ with thorough washing of the filter cake with dichioromethane, followed by flash chromatography (90 g silica gel, pentane-ether,39:1 ; R_f = 0.35) furnished 5-cyclohexyl- 5,6-dimethylhept-6-en-3-yn-2-one (2.5 g, 70%) as a slightly yellowish liquid.

As described in Example 1 for the synthesis of (Z)-5-cyclopentyl-5,6- dimethylhepta-3,6-dien-2-one, from a solution of 5-cyclohexyl-5-hydroxy-6,6- dimethylhept-3-yn-2-one (2.00 g, 9.02 mmol), quinoline (1 drop) and Lindlar catalyst (5% Pd, 66 mg) in ethanol (22 mL) by stirring under hydrogen atmosphere overnight. The insoluble materials were removed by filtration through a pad of Celite™, and thoroughly washed with ethanol. Removal of the solvent under reduced pressure in a rotatory evaporator, and flash chromatography of the resulting residue (300 g silica gel, pentane-ether, 19:1 ; R_f = 0.22) afforded the title compound (Z)-5-cyclohexyl-5,6- dimethylhepta-3,6-dien-2-one (0.90 g, 45%) as a colourless liquid.

Odour description: peppery, dark woody, reminiscent of agarwood and Kephalis (A) with slightly green facets.

IR (neat): 2925, 2852, 1699, 1447, 1350, 1172, 891. 743, 719 cm^-1. ¹H NMR (CDCI₃): 6 = 0.87-1.28 (m. 5 H, cyclohexane ring), 1.18 <s. 3 H, -C(CH₂)-CH₃), 1.42-1.49 (m, 1 H, cyclohexane ring), 1.54-1.61 (m, 1 H, cyclohexane ring), 1.64-1.81 (m, 4 H, cyclohexane ring), 1.70 (dd, J = 0.5, 1.5 Hz, 3 H, CH₉), 2.18 (s, 3 H, -(CO)-CH₃), 4.72 (dd, J = 0.5, 1.5 Hz, 1 H, -C=CHH), 4.83-4.85 (m, 1 H, -C=CHH), 5.85 (d, J = 13.0 Hz, 1 H, -CH=CH-), 6.00 (d, J = 13.0 Hz, 1 H, -CH=C H-).¹³C NMR (CDCI₃): 8 = 19.4 (q), 20.5 (q), 26.8 (t), 27.1 (t), 27.3 <t), 27.4 (t), 28.1 (t), 31.3 (q), 46.3 (d), 48.8 <s), 11 1.9 (t), 129.2 (d), 147.0 (d), 148.4 (s), 201.7 (s). MS: m/z (%) = 29 (11), 43 (89), 55 (60), 79 (29), 83 (15), 95 (100), 123 (94), 137 (63), 138 (13), 177 (4), 220 (1) [M⁴].

Example 3: (Z)-5.6-Dimethyl-5-phenylhepta-3,6-dien-2-one

As described in Example 1 for the synthesis of 1-cyclopentyi-2,2-dimethylpropan-1-one, from a 1.0 M solution of tert-butyl magnesium chloride in tetrahydrofuran (100 mL, 100 mmol), a stirred solution of benzoyl chloride (14.20 g, 100 mmol) and copper(l) chloride (0.50 g, 5.00 mmol, 5.0 mol%) in THF (120 mL). Standard workup followed by flash chromatography (600 g silica gel, pentane-ether, 19:1 ; R, = 0.75) furnished 2,2- dimethyl-1-phenylpropan-1-one (7.7g, 48%) as a colourless liquid.

As described in Example 1 for the synthesis of 5-cyclopentyl-6,6-dimethylhept-3- yne-2,5-diol from a solution of the lanthanum(lll)chloride bis(lithiumchloride) complex (200 mL, 120 mmol, 0.6 M in tetrahydrofuran), a solution of the previously prepared 2,2- dimethyl-1-phenylpropan-1-one (97%, 20.1 g, 120 mmol) in tetrahydrofuran (80 mL), a solution of but-3-yn-2-ol (10.4 g, 144 mmol) in tetrahydrofuran (220 mL), and an ethyl magnesium chloride solution in tetrahydrofuran (2 M, 144 mL, 288 mmol). Standard workup, and purification by flash chromatography (1 kg silica gel, pentane-ether, 1 :1R

= 0.35) of the resulting residue furnished 6,6-dimethyl-5-phenylhept-3-yne-2,5-diol (26.6 g, 95%) as a slightly yellowish liquid.

As described in Example 1 for the synthesis of 5-cyclopentyl-5-hydroxy-6,6- dimethylhept-3-yn-2-one, from 6,6-dimethyl-5-phenylhept-3-yne-2,5-diol (24.3 g, 105 mmol) and a suspension of manganese dioxide (90%, 101 g, 1.05 mol) in dichloromethane (420 mL). Filtration over a short pad of Celite™ with thorough washing of the filter cake with dichloromethane, evaporation of the solvent in a rotatory evaporator, and purification by recrystallization from pentane-ether (9:1) provided 5- hydroxy-6,6-dimethyl-5-phenylhept-3-yn-2-one (18.7 g, 77%) as slightly yellowish crystals (Mp: 81.0 °C - 83.0 °C).

As described in Example 1 for the synthesis of 5-cyclopentyl-5,6-dimethylhept-6- en-3-yn-2-one, from 5-hydroxy-6,6-dimethyi-5-phenylhept-3-yn-2-one (18.65 g, 81 mmol) by stirring in a suspension of Amberiyst^® 15 (37.3 g, 81 mmol) and molecular sieves 4A (74.6 g. 81 mmol) in dichlormethane (190 mL). Filtration over a short pad of Celite™, and thorough washing of the filter cake with dichloromethane, followed by flash chromatography (530 g silica gel, pentane-ether, 14:1 ; R_f = 0.51) furnished 5,6- dimethyl-5-phenylhept-6-en-3-yn-2-one (1.6 g, 9%) as a slightly yellowish liquid.

As described in Example 1 for the synthesis of (Z)-5-cycfopentyl-5,6- dimethylhepta-3,6-dien-2-one, by stirring of a solution of 5,6-dimethyl-5-phenylhept-6- en-3-yn-2-one (2.1 g, 9.89 mmol), pyridine (39 mg, 0.495 mmol) and Lindlar catalyst (5% Pd, 61 mg) in ethanol (21 mL) under hydrogen atmosphere for 3 h. The insoluble materials were removed by filtration through a pad of Celite^{5 M}, and thoroughly washed with ethanol. Removal of the solvent under reduced pressure and flash chromatography (180 g silica gel, pentane-ether, 39:1; R, = 0.16) of the resulting residue afforded (Z)- 5,6-dimethyl-5-phenylhepta-3,6-dien-2-one (1.0 g, 46%) as a colourless liquid.

Odour description: dark-woody, spicy peppery, with additional grapefruit facets and a soft floral, musky effect reminiscent of Cashmeran (B).

IR (neat): 3085, 3056, 2972, 1697, 1445, 1351 , 1173, 896, 759, 699 cm^-1. ¹H NMR (CDCl₃): δ = 1.63 (dd, J = 0.5 Hz, 1.0 Hz, 3 H, CH₂=C-CH₃), 1.65 (s, 3 H, CH₃), 1.99 (s, 3 H, -CO-CH₃). 4.99 (m_c, 2 H, -C=CH₂), 6.04 (d, J = 13.0 Hz. 1 H, -CH=CH-), 6.18 (d, J = 13.0 Hz, 1 H, -CH=CH-), 7.16-7.21 (m, 1 H, Ar-H), 7.26-7.33 (m, 4 H, Ar-H). ¹³C NMR (CDCI₃): δ = 20.5 (q), 25.7 (q), 30.9 (q), 51.2 (s), 1 12.5 (t), 126.2 (d), 127.4 (d), 127.4 (d), 128.0 (d), 128.0 (d), 129.2 (d), 145.5 (d), 145.8 (s), 149.6 (s), 201.6 (s). MS: m/z (%) = 43 (84), 77 (30), 91 (46), 96 (100), 115 (64), 129 (73), 143 (35), 156 (39), 171 (45), 181 (11), 199 (8), 214 (1) [M⁺]. Example 4: (Z)-5-(Bicyclo[2.2.1lheptan-2-yl)-5,6-dimethylhepta-3,e-dien-2-one

At room temperature under N₂ atmosphere, DMF (2 drops) was added to bicyclo[2.2.1]heptane-2-carboxylic acid (25.0 g, 175 mmol). Over a period of 1h, thionyl chloride (31.2 g, 262 mmol) was added with stirring, upon which the temperature dropped to 12 "C with vigorous gas evolution. After 30 minutes of further stirring at room temperature, the temperature was slowly raised to 75 °C, and the reaction mixture then refluxed for 2 h. Distillation of the crude material afforded at 80 °C/200 mbar bicyclo[2.2.1]heptane-2-carbonyi chloride (26.7 g, 92%) as a colourless liquid.

As described in Example 1 for the synthesis of 1-cyclopentyl-2,2- dimethylpropan-1-one, from a 1.7 M solution of tert-butyl magnesium chloride in Et₂O (74.8 mL, 127 mmol), a stirred solution of bicyclo[2.2.1]heptane-2-carbonyl chloride (21.0 g, 127 mmol) and copper(l) chloride (640 mg, 5.00 mmol, 5.0 mo!%) in Et₂O (250 mL). Standard workup followed by flash chromatography (600 g silica gel, pentane- ether,39:1 ; R_f = 0.42) of the resulting residue furnished 1-(bicyclo[2.2.1]heptan-2-yl)- 2,2-dimethylpropan-1-one (15.5 g, 64%) as a colourless liquid.

As described in Example 1 for the synthesis of 5-cyclopentyl-6,6-dimethylhept-3- yne-2,5-diol, from a solution of the lanthanum(lll)chloride bis(lithiumchloride) complex (135 mL, 81 mmol, 0.6 M in tetrahydrofuran), a solution of the previously prepared 1- (bicyclo[2.2.1]heptan-2-yl)-2,2-dimethylpropan-1-one (96%, 15.2 g, 81 mmol) in tetrahydrofuran (65 mL), a solution of but-3-yn-2-ol (7.05 g, 98 mmol) in tetrahydrofuran (165 mL), and an ethyl magnesium chloride solution in tetrahydrofuran (2 M, 98 mL, 195 mmol). Standard workup and purification of the resulting residue by flash chromatography (600 g silica gel, pentane-ether, 1 :1 , R_f - 0.40) furnished 5- (bicyclo(2.2.1]heptan-2-yl)-6,6-dimethylhept-3-yne-2,5-diol (19.5 g, 96%) as a slightly yellowish liquid.

As described in Example 1 for the synthesis of 5-cyclopentyl-5-hydroxy-6,6- dimethylhept-3-yn-2-one, from 5-(bicyclo[2.2.1]heptan-2-yl)-6,6-dimethylhept-3-yne-2,5- diol (19.5 g, 78 mmol) with a suspension of manganese dioxide (90%, 75 g, 779 mmol) in dichloromethane (250 mL). Filtration over a short pad of Celite™ with thorough washing of the filter cake with dichloromethane, removal of the solvent in a rotatory evaporator, and purification of the resulting residue by flash chromatography (600 g silica gel, pentane-ether, 3:1 , R_f = 0.60) furnished 5-(bicycto[2.2.1]heptan-2-yl)-5- hydroxy-6,6-dimethylhept-3-yn-2-one (16.1 g, 82%) as a slightly yellowish liquid.

As described in Example 1 for the synthesis of 5-cyclopentyl-5,6-dtmethylhept-6- en-3-yn-2-one, from 5-(bicyclo[2.2.1]heptan-2-yl)-5-hydroxy-6,6-dimethylhept-3-yn-2- one (16.1 g, 63.7 mmol) with a stirred suspension of Amberlyst^® 15 (32.2 g, 63.7 mmol) and molecular sieves 4A (64.4 g, 63.7 mmol) in dichlormethane (160 mL). Filtration over a short pad of Celite™, and thorough washing of the filter cake with dichJoromethane, followed by flash chromatography (600 g silica gel, pentane- ether,19:1; R_f = 0.45) furnished 5-(bicyclo[2.2.1]heptan-2-yl)-5,6-dimethylhept-6-en-3-2- one (1.60 g, 35%) as a slightly yellowish liquid.

As described in Example 1 for the synthesis of (Z)-5-cyclopentyl-5,6- dimethylhepta-3,6-dien-2-one, by stirring of a solution of 5-(bicyclo[2.2.1]heptan-2-yl)- 5,6-dimethylhept-6-en-3-2-one (1.60 g. 6.61 mmol), pyridine (26.0 mg, 0.331 mmol) and Lindlar catalyst (5% Pd, 41 mg) in ethanol (15 mL) under hydrogen atmosphere for 2 h 30 minutes. The insoluble material was removed by filtration through a pad of Celite™, and thoroughly washed with ethanol. Removal of the solvent under reduced pressure in a rotatory evaporator and flash chromatography (180 g silica gel, pentane-ether, 39:1 ; R_f = 0.27, 19:1) of the resulting residue afforded <Z)-5-(bicyclo[2.2.1]heptan-2-yl)-5,6- dimethylhepta-3,6-dien-2-one (0.30 g, 19%) as a colourless liquid.

Odour description: dark woody, peppery, with metallic, fruity aspects.

IR (neat): 2947, 2869, 1698, 1350, 1172, 971 , 889, 734 cm^-1. ¹H NMR (CDCI₃): δ = 0.98-1.03 (ddd, J = 4.0, 6.5, 10.0 Hz, 1 H, bicyclic ring), 1.11-1.23 (m, 2 H, bicyclic ring), 1.29 (s, 3 H, CH₃), 1.32-1.35 (m, 1 H, bicyclic ring), 1.52-1.72 (m, 3 H, bicyclic ring), 1.73 (d, J = 1.0 Hz, 3 H, CH₂=C-CH₃), 1.91-1.98 (m, 1 H, bicyclic ring), 2.14 (s, 3 H, -(CO)-CH₃), 2.18-2.19 (m, 2 H, bicyclic ring), 2.26-2.28 (m, 1 H, bicyclic ring), 4.69 (dd, J = 0.5, 1.5 Hz, 1 H, -C=CHH), 4.75-4.77 (m, 1 H, -C=CHH), 6.08 (d, J = 13.0 Hz, 1 H, -CH=CH-), 6.16 (d, J = 13.0 Hz, 1 H, -CH=CH-). ¹³C NMR (CDCI₃): δ = 21.2/21.1 (2q), 24.3 (2t), 25.1 (2q), 29.8 (2t), 31.3 (2q), 31.6 (2t), 37.5 (2d), 40.6 (2d), 41.2 (2t), 47.4 (2s), 49.8/50.9 (2d), 1 10.4 (2t), 127.7 (2d), 148.0 (2d), 149.5 (2s), 199.9 (2s). MS: m/z (%) = 43 (24), 67 (22), 79 (13), 95 (100), 110 (40), 123 (27), 137 (23), 138 (7), 217 (1), 232 (1) [Ml.

Example 5: (Z)-6-Ethyl-5-methyl-5-(prop-1-en-2-yl)oct-3-en-2-one

At -78 °C, a 2.7 M solution of n-buthyllithium in heptane (310 mL, 837 mmol) was added dropwise within 2 h to a stirred solution of isopropylamine (140 mL, 982 mmol) in tetrahydrofuran (645 mL). After stirring for 1 h at -78 °C the reaction mixture was allowed to warm to 0 °C, and then was cooled back to -78 °C again. A solution of DMPU (100 mL, 827 mmol) in tetrahydrofuren (600 mL) was added dropwise within 2 h, and the reaction mixture was stirred for 15 minutes at -78 ºC, prior to dropwise addition of a solution of 2,2-dimethylhexan-3-one (100 g, 757 mmol) in tetrahydrofuran (500 mL) within 2 h. lodoethane (100 mL, 1.21 mmol) was then added dropwise with stirring over a period of 1h 15 minutes, and stirring was continued at room temperature over night. The reaction was quenched by addition of saturated ammonium chloride solution (1 L) and the organic layer was separated. The aqueous layer was extracted with diethyf ether (2 x 1 L), and the combined organic extracts were washed with water (1 x 1 L) and brine (1 x 500 mL), dried (Na₂SO₄), and concentrated under reduced pressure on the rotatory evaporator. Distillation in vacuo (100 mbar, 80 -110 °C) provide 4-ethyl-2,2- dimethyIhexan-3-one (118 g, 45%) as a colourless liquid.

As described in Example 1 for the synthesis of 5-cyclopentyl-6,6-dimethylhept-3- yne-2,5-diol, from a solution of the lanthanum(lll)chloride bis(lithiumchtoride) complex (400 mL, 240 mmo), 0.6 M in tetrahydrofuran), a solution of the previously prepared 4- ethyl-2,2-dimethylhexan-3-one (97%, 37.5 g, 240 mmo!) in tetrahydrofuran (100 mL), a solution of but-3-yn-2-ol (18.5 g, 264 mmol) in tetrahydrofuran (580 mL), and an ethyl magnesium chloride solution in tetrahydrofuran (2 M, 288 mL, 576 mmol). Standard workup and purification by flash chromatography (2 kg silica gel, pentane-ether, 2:1 , R_f = 0.24) of the resulting residue provided 5-( tert-butyl)-6-ethyloct-3-yne-2,5-dio! (50.7 g, 93%) as a slightly yellowish liquid.

As described in Example 1 for the synthesis of 5-cyclopentyl-5-hydroxy-6,6- dimethy!hept-3-yn-2-one, from 5-(tert-butyl)-6-ethyloct-3-yne-2,5-diol (15.1 g, 64.8 mmol) with a suspension of manganese dioxide (90%, 62.6 g, 648 mmol) in dichloromethane (200 mL). Filtration over a short pad of Celite^™ with thorough washing of the filter cake with dichloromethane, furnished after concentration of combined extracts under reduced pressure in a rotatory evaporator, crude 5-(tert-butyl)-6-ethyl-5- hydroxyoct-3-yn-2-one (14.3 g, 95%) as a slightly yellowish liquid that was employed in the next step without further purification.

As described in Example 1 for the synthesis of 5-cyclopentyl-5,6-dimethylhept-6- en-3-yn-2-one, from the crude 5-(tert-butyl)-6-ethyl-5-hydroxyoct-3-yn-2-one (14.3 g, 61.8 mmol) in a stirred suspension of Amberlyst^® 15 (28.6 g, 61.8 mmol) and molecular sieves 4A (57.2 g, 61.8 mmol) in dichlorm ethane (140 mL). Filtration over a short pad of Celite™ with thorough washing of the filter cake with dichloromethane, evaporation of the solvent in a rotatory evaporator, and flash chromatography (300 g silica gel, pentane-ether, 39:1 ; R_f = 0.31) furnished 6-ethyl-5-methyl-5-(prop-1-en-2-yl)oct-3-yn-2- one (6.4 g, 45%) as a slightly yellowish liquid.

As described in Example 1 for the synthesis of (Z)-5-cyclopenty 1-5,6- dimethylhepta-3,6-dien-2-one, by stirring a solution of 6-ethyl-5-methyl-5-(prop-1-en-2- yl)oct-3-yn-2-one (90%, 6.4 g, 27.9 mmol), pyridine (110 mg, 1.39 mmol) and Lindlar catalyst (5% Pd, 173 mg) in ethanol (50 mL) under hydrogen atmosphere for 2 h 45 minutes. The insoluble materials were removed by filtration through a pad of Celite™, and thoroughly washed with ethanol. Removal of the solvent under reduced pressure in a rotatory evaporator, and flash chromatography (600 g silica gel, pentane-ether, 39:1; R_f = 0.12) of the resulting residue afforded (Z)-6-ethyl-5-methyl-5-(prop-1-en-2-yl)oct-3- en-2-one (5.0 g, 86%) as a colourless liquid.

Odour description: dark woody, spicy, peppery, reminiscent of Kephalis (A) and Cashmeran (B).

IR (neat): 2960, 2936, 2875, 1700, 1379, 1351 , 1173, 970, 892, 734 cm ¹. ¹H NMR (CDCI₃): δ = 0.92-1.00 (m, 6 H, 2 CH₃), 1.04-1.20 (m, 2 H, -CH₂-CH-CH₂-), 1.18 (s, 3

H, CHj), 1.26-1.30 (m, 1 H, -CH₂-CH-CH₂-), 1.40-1.57 (m, 2 H, -CH₂-CH-CH₂-).

I .72 (s, 3 H, -C(CH₂)-CH₃), 2.19 (s, 3 H, -CO-CH₃), 4.78 (s, 1 H, -C=CHH), 4.86 (s, 1 H, -C=CHH), 5.80 (d, J = 13.0 Hz, 1 H, -CH=CH-), 6.01 (d. J = 13.0 Hz, 1 H, - CH=CH-). ¹³C NMR (CDCI₃): δ = 14.6 (q), 14.9 (q), 19.7 <q), 20.4 (q), 23.8 (t), 24.7 (t), 31.3 (q), 49.6 (d), 50.7 (s), 112.0 (t), 129.3 (d), 146.9 (d), 148.8 (s), 201.9 (s). MS: m/z (%) = 29 (7), 43 (67), 79 (15), 95 (72), 123 (100), 137 (59), 179 (3), 165 (2), 193 (1), 208 (1) [M^*].

Example 6: (Z)-5,6-Dimethyl-5-(prop-1-en-2-yl)oct-3-en-2-one

As described for the synthesis of 4-ethyl-2,2-dimethylhexan-3-one in Example 5, from a solution of n-buthyllitriium (170 mL, 459 mmol, 2.7 M in heptane), a solution of isopropylamine (77 mL, 542 mmol) in tetrahydrofuran (355 mL), a solution of DMPU (55.3 mL, 459 mmol) in tetrahydrofuran (330 mL), a solution of 2,2-dimethylhexan-3- one (97%, 53.5 g, 417 mmol) in tetrahydrofuran (280 mL) and iodomethane (42.6 mL, 668 mmol). Standard workup and purification of the resulting residue by distillation in vacuo afforded 2,2,4-trimethylhexan-3-one (52.1 g, 69%) as a slightly yellowish liquid. As described in Example 1 for the synthesis of 5-cycfopentyl-6,6-dimethylhept-3- yne-2,5-diol, from a solution of the lanthanum(llt)chloride bis(lithiumchloride) complex (400 mL, 240 mmol, 0.6 M in tetrahydrofuran), a solution of the previously prepared 2,2,4-trimethyIhexan-3-one (78%, 43.8g, 240 mmol) in tetrahydrofuran (110 mL), a solution of but-3-yn-2-ol (19.1 g, 264 mmol) in tetrahydrofuran (650 mL), and an ethyl magnesium chloride solution in tetrahydrofuran (2 M, 288 mL, 576 mmot). Standard workup and purification of the resulting residue by flash chromatography (1.8 kg silica gel, pentane-ether, 1:1, R_f = 0.28) provided 5-tert-butyl-6-methyloct-3-yne-2,5-diol (27.0 g, 38%) as a slightly orange liquid.

As described in Example 1 for the synthesis of 5-cyclopentyl-5-hydroxy-6,6- dimethylhept-3-yn-2-one, from 5-tert-butyl-6-methyloct-3-yne-2,5-diol (24.0 g, 1 13 mmol) in a suspension of manganese dioxide (90%, 147 g, 1.70 mol) in dichloromethane (600 mL). Filtration over a short pad of Celite™ with thorough washing of the filter cake with dichloromethane, concentration of the combined filtrate and washings under reduced pressure in a rotatory evaporator, and purification of the resulting residue by flash chromatography (1 kg silica gel, pentane-ether, 5:1 , R_f = 0.42 furnished 5- tert-butyl-5-hydroxy-6-methyloct-3-yn-2-one (5.10 g, 21%) as a slightly yellowish liquid.

As described in Example 1 for the synthesis of 5-cyclopentyl-5,6-dimethylhept-6- en-3-yn-2-one, from 5-tert-butyl-5-hydroxy-6-methyloct-3-yn-2-one (7.20 g, 33.6 mmol) in a stirred suspension of Amberlyst^® 15 (14.4 g, 33.6 mmol) and molecular sieves 4A (28.8 g, 33.6 mmol) in dichloromethane (75 mL). Filtration over a small pad of Celite™ with thorough washing of the filter cake with dichloromethane, concentration of the combined filtrate and extracts under reduced pressure in a rotatory evaporator, and purification of the resulting residue by flash chromatography (120 g silica gel, pentane- ether,39: 1 ; R_f = 0.24) provided 5,6-dimethyl-5-(prop-1-en-2-yI)oct-3-yn-2-one (4.40 g, 66%) as a slightly yellowish liquid.

As described in Example 1 for the synthesis of (Z)-5-cyclopentyl-5,6- dimethylhepta-3,6-dien-2-one, by stirring a solution of 5.6-dimethyl-5-(prop-1-en-2- yI)oct-3-yn-2-one (97%, 1.80 g, 9.04 mmol), pyridine (36 mg, 0.45 mmol) and Lindlar catalyst (5% Pd, 56 mg) in ethanol (13 mL) under hydrogen atmosphere for a total of 4 h 40 minutes, with addition of a second portion of Lindlar catalyst (56 mg) after 2 h of stirring. The insoluble materials were removed by filtration through a pad of Celite™ , and thoroughly washed with ethanol. Concentration of the combined filtrate and washings under reduced pressure in a rotatory evaporator, and flash chromatography (300 g silica gel, pentane-ether, 19:1 = 0.32) of the resulting residue provided (Z)- 5,6-dimethyl-5-(prop-1-en-2-yl)oct-3-en-2-one (1.10 g, 63%) as a slightly yellowish liquid.

IR (neat): 2963, 2933, 2876, 1699, 1453, 1378, 1351 , 1 172, 970, 892, 735 cm^{' 1}. ¹H NMR (CDCI₃): δ = 0.77/0.88 (2d, J = 7.0 Hz, 3 H, CH₃). 0.89-0.97 (m, 1 H, -CH- CHH-CH₃), 0.92/0.93 (2t, J = 6.5 Hz, 3 H, CH₃), 1.14/1.16 (2s, J = 7.0 Hz. 3 H, CH₃), 1.43-1.58 (m, 2 H, -CHCH₃-CH₂, -CH-CHH-CH₃), 1.70 (br. s, 3 H, -C(CH₂)-CH₃), 2.18/2.19 (2s, 3 H, -CO-CH₃), 4.76 (s, 1 H, -C=CHH), 4.83-4.86 (m, 1 H, -C=CHH), 5.78 / 5.79 (2d, J = 13.0 Hz, 1 H, -CH=CH-), 6.00 / 6.01 (2d, J = 13.0 Hz, 1 H, - CH=CH-). ¹³C NMR (CDCI₃): R = 13.0/13.3 (2q), 13.4/14.1 (2q), 18.7/18.8 (2q), 20.3/20.5 (2q), 24.1/24.9 (2t), 31.3 (2q), 42.3/42.6 (2d), 49.5/49.6 (2s), 1 11.9/112.1 (2t), 129.2/129.5 (2d). 146.7/146.8 (2d), 148.5/148.7 (2s), 201.8/201.9 (2s). MS: m/z (%) = 29 (10), 43 (100), 79 (16), 95 (68), 123 (62), 137 (46), 165 (3), 179 (1),194 (1) [M^*].

Example 7: Modern Fioral-fresh Musk Cologne with Peppery Dark-Woody Contrast

Less than 3% of (Z)-5-cyclopentyl-5,6-dimethylhepta-3,6-dien-2-one impart this modern musk cologne-type fragrance with a warm peppery signature, and a special dark woody-musky contrast recalling agarwood, albeit this is not the main character of the perfume. In addition, (Z)-5-cyclopentyl-5,6-dimethylhepta-3,6-dien-2-one pushes the floral elements of the composition, wraps the hesperidic citrusy notes, and thereby provides more juiciness. The incorporation of (Z)-5-cyclopentyl-5,6-dimethyihepta-3,6- dien-2-one greatly increases the volume of the perfumes, and much enhances its diffusion, while contributing also significantly to a very nice and attractive dry-down.

Example 8: Fruitv-F I oral-Wood v Floriental Feminine Fragrance

At almost 9%, (Z)-5-cyclopentyl-5.6-dimethylhepta-3,6-dien-2-one provides this fruity- floral-woody floriental feminine fragrance with a strong woody-peppery signature, recalling agarwood facets. In this composition, (Z)-5-cyclopentyl-5,6-dimethylhepta-3,6- dien-2-one blends particularly well with vanillin, Florymoss and Evernyl, thereby much increasing the sensual part of the central base-note accord. (Z)-5-Cyclopentyl-5,6- dimethylhepta-3,6-dien-2-one also actively contributes to the technical performance of the fragrance, especially its diffusion and trail (sillage).

Claims

Claims 1 . A compound of the formula (t) with (Z)-configured α,β-unsaturated double bond

wherein

Y is selected from phenyl, bicyclo[2.2.1]heptan-2-yl, and -CHR¹R², wherein R¹ and R² are independently selected from methyl and ethyl, or R¹ and R² form together with the carbon atom to which they are attached cyclo-C₅-C₇-alkyl. 2. A compound according to claim 1 selected from the group consisting of (Z)-5- cyclopentyl-5,6-dimethylhepta-3,6-dien-2-one, (Z)-5-cyclohexyl-5-6-dimethylhepta-3,6- dien-2-one, (Z)-5,6-dimethyl-5-phenylhepta-3,6-dien-2-one, (Z)-5- (bicyclo[2.

2.1 ]heptan-2-yl)-5,6-dimethylhepta-3,6-dien-2-one, (Z)-6-ethyl-5-methyl-5- (prop-1-en-2-yt)oct-3-en-2-one, and (Z)-5,6-dimethyl-5-(prop-1-en-2-yl)oct-3-en-2-one.

3. The use as fragrance of a compound of formula (I) with (Z)-conftgured α,β-unsaturated double bond

wherein

Y is selected from phenyl, bicyclo[2.2.1]heptan-2-yl, and -CHR¹R², wherein R¹ and R² are independently selected from methyl and ethyl, or R¹ and R² form together with the carbon atom to which they are attached cyclo-C₅-C₇-alkyl.

5. A fragrance composition or a perfumed product comprising a compound of formula (I

) as defined in claim 1.

6. A perfumed product according to claim 5 wherein the product is selected from fine perfumery, fabric care, household products, beauty and personal care products and air care products.

7. A method of improving, enhancing, or modifying a consumer product base comprising the step of adding thereto an olfactorily acceptable amount of at least one compound of formula (t) as defined in claim 1 , or a mixture thereof.