6,6-DIMETHYLBICYCLO[3.1.0]HEXANE DERIVATIVES 109 HO-..L/R _- 7 R =Me, X=I 8 R =Et, X=I 9 R =All, X= Br -.....•_ OAc _'•_'•CN b=Z •0 •6 a, b RMgX• 1. LiAIH412. AcCl -- - 1. NaOBr [• :2. LiAIH 4 3. PCC '•gBr •O w• 21a, b R=-CN W• 22 a R = -Pc W• 23a R =-COOEt PCC = [PyH]ClCrO 3 •COOE{ 11 a,b 20 13 1. LiAIH 4 2 PCC CN f7 •COOEt f2 W• = (EtO)•P(O)CH•COOEt W2 = (EtO)•P(O)CH2CN W3 = (CSH5)3 P=CH CCH3 II o Scheme 2 with W 3 (acetonylidenetriphenylphosphate) gave the pure isomer (E) of ot,•3-unsaturated ketone 22a, and the Wadsworth-Emmons procedure with W1 transformed 19 into the pure isomer (E) of ot,•3-unsaturated ester 23a, which after hydrogenation in the presence of Raney-nickel was converted into the saturated ester 24 (10). Reduction of 24 with

110 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS LiAIH 4 afforded alcohol 25 (11). It is worth noting that the direct reduction of ester 23a with LiAIH4 gave the same result. Summing up, synthesis of eighteen new compounds containing the gem- dimethylbicyclo[3.1.0]hexane system substituted at C-3 and differing with the position of the double bond and with the kind of functional group (alcohol, ester, nitrile, ketone) allowed us to study the odor characteristics of this group of compounds in some detail. Generally, derivatives of bicyclo[3.1.0]hexane exhibit stronger odor properties than corresponding derivatives of cyclohexane (4). As seen from Table I, the obtained com- pounds may be classified into several groups, based on their odor properties. The first group is composed of alcohols 7, 8, 9, 14, 20, and 25, which exhibit medium- intensive floral odors with various notes, depending on their chemical structure. For example, tertiary alcohols possess a lilac-woody note (7,8) and a fungal note (9), Table I Physicochemical Constants and Odor Characteristics of 3-Substituted-6,6-Dimethylbicyclo[3.1.0]Hexane Derivatives Yield • b.p. Odor Compound (%) (øC/mm Hg) nD 2ø characteristics 7 80.0 67/3 1.4798 8 93.0 69/3 1.4828 9 78.0 86/1 1.4878 10 71.0 89/4 1.4577 11a,b 68.6 112-116/4 1.4763 12 63.4 90/2 1.4655 13 -- -- -- 14 17.0 105/1 1.4865 15a 18.1 131/4 1.4938 16a,b 50.5 99-101/4 1.5027 17 42.8 101-104/4 1.4935 18 46.5 94/4 1.4812 20 22.0 94/4 1.4867 21a,b 49.7 99-101/4 1.4878 22a 28.0 111/4 1.4958 23a 26.2 117/6 1.4779 24 24.6 89/2 1.4660 25 22.1 89/4 1.4745 Medium-intensive floral, with lilac and turpentine note Medium-intensive floral, with weaker lilac and turpentine note than 7 Medium-intensive floral, with agreeable fungal note Medium-intensive, agreeable, fresh, floral, with lilac, lavender, and woody note Medium-intensive fruity, with bildberry note Medium-intensive, agreeable, fruity, with apple note, similar to 1 la,b Sharp, penetrating, fruity-fiora, with citrus note Medium-intensive, agreeable, floral, with marked moldy note Medium-intensive, agreeable, fresh, fruity Intensive, penetrating, fresh, with lemon-cumin note Medium-intensive, penetrating, less fresh, with less lemon-cumin not than 16a,b Intensive, penetrating, fresh, with weaker lemon-cuminic note than 16a,b Medium-intensive, penetrating, floral, with fruity-moldy note Intensive, penetrating, cuminic, with aniseed note Medium-intensive, agreeable, fresh, floral, [3-ionone-like, with woody note Medium intensive, agreeable, fresh, fruity, with mango and wild-strawberry note Medium-intensive, agreeable, fresh, fruity with weaker wild-strawberry note than 12 Medium-intensive, agreeable, floral, with leaf-green note Yields calculated on 6.