PENTAALKYLSTIBORANES .1. SYNTHESIS OF HOMOBENZYLIC ALCOHOLS, HOMOALLYLIC ALCOHOLS, ETHYL 5-ARYL-5-HYDROXYPENT-2-ENOATES, AND BETA-HYDROXYPROPIONIC ACID-DERIVATIVES VIA PENTAALKYLSTIBORANES

Although pentaalkylstiboranes have long been known, their applications in organic synthesis have not been exploited. It has been found that quaternary stibonium salts (n-Bu3SbCH2E]+X- (E = Ph, CH = CH2, CH = CHCO2Et, CO2Et, CN; X = Br, I, BPh4) on treatment with RLi (R = n-Bu, t-Bu, Ph) afford pentaalkylstiboranes, n-Bu3Sb(R)CH2E, which react with aromatic aldehydes to give, after subsequent hydrolysis, homobenzylic alcohols, homoallylic alcohols, ethyl 5-aryl-5-hydroxypent-2-enoates, ethyl beta-aryl-beta-hydroxypropionates, and beta-aryl-beta-hydroxypropionitriles, respectively, in good to excellent yields. The reaction is chemoselective for aldehydes.