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

Article abstract of DOI:10.1002/hlca.19930760521

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.