140632-41-3

Upstream product

• 153060-96-9 (+)-(1R,5S)-2,5,6,6-tetramethylcyclohex-2-ene-1-methanol 
• 634611-85-1 ((3S,4R,6S)-5,5,6-Trimethyl-1-oxa-spiro[2.5]oct-4-yl)-methanol 
• 153060-93-6 (-)-(1R,3S)-2,2,3-trimethyl-6-methylidenecyclohexane-1-methanol 
• 140479-11-4 (+)-(3R,5S)-4,4,5-trimethyl-8-methylidene-1-oxaspiro<2.5>octane 
• 140479-12-5 (+)-(3S)-2,2,3-trimethyl-6-methylidenecyclohexan-1-one 

Relevant academic research and scientific papers

Competitive Gold-Promoted Meyer-Schuster and oxy-Cope Rearrangements of 3-Acyloxy-1,5-enynes: Selective Catalysis for the Synthesis of (+)-(S)-γ-Ionone and (-)-(2S,6 R)-cis-γ-Irone

We report a simple, highly stereoselective synthesis of (+)-(S)-γ-ionone and (-)-(2S,6R)-cis-γ-irone, two characteristic and precious odorants; the latter compound is a constituent of the essential oil obtained from iris rhizomes. Of general interest in this approach are the photoisomerization of an endo trisubstituted cyclohexene double bond to an exo vinyl group and the installation of the enone side chain through a [(NHC)AuI]-catalyzed Meyer-Schuster-like rearrangement. This required a careful investigation of the mechanism of the gold-catalyzed reaction and a judicious selection of reaction conditions. In fact, it was found that the Meyer-Schuster reaction may compete with the oxy-Cope rearrangement. Gold-based catalytic systems can promote either reaction selectively. In the present system, the mononuclear gold complex [Au(IPr)Cl], in combination with the silver salt AgSbF6 in 100:1 butan-2-one/H2O, proved to efficiently promote the Meyer-Schuster rearrangement of propargylic benzoates, whereas the digold catalyst [{Au(IPr)}2(μ-OH)][BF4] in anhydrous dichloromethane selectively promoted the oxy-Cope rearrangement of propargylic alcohols.

Electrophilic Cyclization of 1,6-Dienes Containing an Allylsilane Moiety - Enantioselective Synthesis of cis- and trans-γ-Irone

In this paper, we report the first examples of Lewis acid and mercuric trifluoroacetate promoted cyclizations of 1,6-dienes containing an allylsilane moiety. Mercuric trifluoroacetate has been proved to be the reagent of choice leading to methylenecyclohexane derivatives in good yields and with complete regioselectivity albeit with poor diastereoselectivity. Using this methodology a stereodivergent synthesis of enantiomerically pure (-)-(2S,6R)-cis-γ -irone and (-)-(2S,6S)-trans-γ-irone, two precious aroma constituents, has been accomplished. This represents an innovative approach with respect to previous syntheses of γ-irones. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003.

Preparation of Optically Active Flowery and Woody-Like Odorant Ketones via Corey-Chaykovsky Oxiranylation: Irones and Analogues

α-, β-, and γ-Irones and analogues have been prepared from optically active (+)-1, (+)-6a,b, and (+)-17, via a Corey-Chaykovsky oxiranylation (Me2S, Me2SO4, Me2SO, NaOH) followed by isomerisation (SnCl4 or MgBr2). (+)-Dihydrocyclocitral (19a), obtained from (-)-citronellal, and analogue (+)-19b, were condensed with various ketones to afford (+)-21a-f, and after hydrogenation (+)-22a-f.A mild oxidative degradation of aldehydes (+)-trans- and (-)-cis-8a,b to ketones (-)-16a,b, as well as olfactive evaluations, 13C-NMR assignments, and absolute configurations of the intermediate epoxides, aldehydes, and alcohols are presented.

Cyclic ketones and their use as perfuming ingredients

Novel compounds of formula STR1 wherein the dotted lines indicate the location of a single or double bond, symbol R1 stands for a hydrogen atom or a methyl radical, symbol R2 represents a linear or branched, saturated or unsaturated, C1 to C4 alkyl radical, provided that R1 is not hydrogen when R2 represents a methyl or n-propyl radical and the ring is saturated. Compounds (Ia) are useful as perfuming ingredients. A process for their preparation is disclosed.