【文章名】Exaltone (R) (=Cyclopentadecanone) from Isomuscone (R) (=Cyclohexadecanone), a One-C-Atom Ring-Contraction Methodology via a Stereospecific Favorskii Rearrangement: Regioselective Application to (-)-(R)-Muscone
Exaltone (R) (=Cyclopentadecanone) from Isomuscone (R) (=Cyclohexadecanone), a One-C-Atom Ring-Contraction Methodology via a Stereospecific Favorskii Rearrangement: Regioselective Application to (-)-(R)-Muscone
作者
Chapuis, C; Robvieux, F; Cantatore, C; Saint-Leger, C; Maggi, L
[摘要]:Treatment of cyclohexadecanone (1g; with I2 (2.2 mol-euqiv.) and KOH in MeOH) furnished the unsaturated (Z)-ester 2g in 83% yield, via a stereospecific Favorskii rearrangement (Scheme 1). Further treatment with 3-chloroperbenzoic acid (m-CPBA) afforded the unreported epoxy ester 3g (88% yield), which was cleaved in 33% yield to Exaltone (R) (=cyclopentadecanone; 1f) with NaOH in MeOH/H2O and then HCl at 65 degrees. This methodology was similarly extended to higher (C17) and lower (C15 to C11) cyclic ketone analogues, as well as regioselectively to (-)-(R)-muscone (5c) and homomuscone (5f) (Scheme 2). Olfactive properties of the corresponding macrocyclic 1-oxaspiro[2,n]alkanes and -alkenes 4 and 8, resulting from a Corey?Chaykovsky oxiranylation, are also presented.