35124-16-4Relevant articles and documents
Enzyme-Mediated Preparation of (+)- and (-)-β-Irone and (+)- and (-)-cis-γ-Irone from Irone alpha
Brenna, Elisabetta,Delmonte, Marco,Fuganti, Claudio,Serra, Stefano
, p. 69 - 86 (2007/10/03)
The (-)- and (+)-β-irones ((-)- and (+)-2, resp.), contaminated with ca. 7-9 percent of the (+)- and (-)-trans-α-isomer, respectively, were obtained from racemic α-irone via the 2,6-trans-epoxide (+/-)-4 (Scheme 2). Relevant steps in the sequence were the LiAlH4 reduction of the latter, to provide the diastereoisomeric-4,5-dihydro-5-hydroxy-trans-α-irols (+/-)-6 and (+/-)-7, resolved into the enantiomers by lipase-PS-mediated acetylation with vinyl acetate. The enantiomerically pure allylic acetate esters (+)- and (-)-8 and (+)- and (-)-9, upon treatment with POCl3/pyridine, were converted to the β-irol acetate derivatives (+)- and (-)-10, and (+)- and (-)-11, respectively, eventually providing the desired ketones (+)- and (-)-2 by base hydrolysis and MnO2 oxidation. The 2,6-cis-epoxide (+/-)-5 provided the 4,5-dihydro-4-hydroxy-cis-α-irols (+/-)-13 and (+/-)14 in a 3:1 mixture with the isomeric 5-hydroxy derivatives (+/-)-15 and (+/-)-16 on hydride treatment (Scheme 1). The POCl3/pyridine treatment of the enantiomerically pure allylic acetate esters, obtained by enzymic resolution of (+/-)-13 and (+/-)-14, provided enantiomerically pure cis-α-irol acetate esters, from which ketones (+)- and (-)-22 were prepared (Scheme 4). The same materials were obtained from the (9S) alcohols (+)-13 and (-)-14, treated first with MnO2, then with POCl3/pyridine (Scheme 4). Conversely, the dehydration with POCl3/pyridine of the enantiomerically pure 2,6-cis-5-hydroxy derivatives obtained from (+/-)-15 and (+/-)-16 gave rise to a mixture in which the γ-irol acetates 25a and 25b and 26a and 26b prevailed over the α- and β-isomers (Scheme 5). The (+)- and (-)-cis-γ-irones ((+)- and (-)-3, resp.) were obtained from the latter mixture by a sequence involving as the key step the photochemical isomerization of the α-double bond to the γ-double bond. External panel olfactory evaluation assigned to (+)-β-irone ((+)-2) and to (-)-cis-γ-irone ((-)-3) the strongest character and the possibility to be used as dry-down note.
Enzyme-mediated syntheses of the enantiomers of γ-irones
Brenna, Elisabetta,Fuganti, Claudio,Ronzani, Sabrina,Serra, Stefano
, p. 3650 - 3666 (2007/10/03)
An enzymatic approach to the synthesis of all the possible stereoisomers of (E) and (Z), cis and trans-γ-irones in enantiomerically pure form from commercial Irone Alpha is described. A very efficient resolution of racemic trans-γ-irone, affording both the enantiomers in high ee and chemical purity, is also presented. Olfactory evaluation of (+)- and (-)-3b and full configuration assignment of the irone isomers contained in samples of Italian iris oil are reported.
Synthesis of both enantiomers of cis-α-irone and cis-γ-irone, principal constituents of iris oil, via resolution of (±)-2,2,4-trimethyl-3-cyclohexene-1-carboxylic acid
Inoue, Takahiro,Kiyota, Hiromasa,Oritani, Takayuki
, p. 3807 - 3818 (2007/10/03)
The principal constituents of iris oil, (-)-cis-α-irone and (-)-cis-γ-irone, and their enantiomers, were synthesized from (-)- and (+)-2,2,4-trimethyl-3-cyclohexene-1-carboxylic acids. The racemic acid was resolved by recrystallization of its salt with a chiral amine, or by enzymatic hydrolysis of the corresponding alcohol. The fragrances of (-)-(1R,5S)-cis-α-irone and (-)-(1R,5S)-cis-γ-irone were superior to those of (+)-(1S,5R)-cis-α-irone and (+)-(1S,5R)-cis-γ-irone. Copyright (C) 2000 Elsevier Science Ltd.
Synthesis of (+)-(2S,6S)-trans-α-Irone and of (-)-(2S,6S)-trans-γ-Irone
Helmlinger, Daniel,Frater, Georg
, p. 1515 - 1521 (2007/10/02)
A 3:1 mixture of (+)-(2S,6S)-trans-α-irone ((+)-1) and (-)-(2S,6S)-trans-γ-irone ((-)-2) has been synthesized with ca. 70 percent e. e. by the ene reaction of (-)-(S)-3 and but-3-yn-2-one.
Syntheses of (+/-)-cis γ-Irone and Its Related Compounds
Kawanobe, Tsuneo,Iwamoto, Minoru,Kogami, Kunio,Matsui, Masanao
, p. 791 - 796 (2007/10/02)
(+/-)-cis-γ-Irone (1a), (+/-)-cis-dihydro-γ-irone (2a) and their trans-isomers (1b, 2b) were synthesized via 3,3-(Claisen) or 2,3-sigmatropic rearrangement of 1-hydroxymethyl-3,3,4-trimethyl-1-cyclohexene (8) derivatives as each key step.
CHIMIE DES FRAGRANCES, PARTIE II: SYNTHESE DE LA γ-IONONE ET DES CIS- ET TRANS-γ-IRONES
Leyendecker, Francois,Comte, Marie-Therese
, p. 85 - 92 (2007/10/02)
A new convergent synthesis of γ-ionone and cis- and trans-γ-irones is described.A tandem 1,4-addition functionnalisation reaction and a chemo- and regioselective olefination reaction are the key steps.A two dimensional NMR study allows the determination of the favoured configuration of one intermediate.
New Synthesis of trans-γ-Irone
Takazawa, Osamu,Kogami, Kunio,Hayashi, Kazuo
, p. 389 - 390 (2007/10/02)
trans-γ-Irone was successfully synthesized starting from 3,4-dimethyl-2-cyclohexenone by sevenstep reactions including TiCl4-promoted reaction of enol silyl ether and cross-aldol reaction of vinyloxyborane.
The Synthesis of (+/-)-γ-Irones
Kitahara, Takeshi,Tanida, Kaichi,Mori, Kenji
, p. 581 - 586 (2007/10/02)
(+/-)-γ-Irones (1/9 of cis- and trans-isomers and pure trans-γ-irone) were synthesized via the intramolecular Diels-Alder reaction starting from 2,4-hexadienyl aniline derivative and β,β-dimethylacryloyl chloride.
