Oxidation of acyclic alkenes and allyl and benzyl ethers with DIB/ t-BuOOH/Mg(OAc) 2

Abstract

Oxidation of (11 Z)-1′,2′-didehydrostemofoline with DIB/TBHP/Mg(OAc) 2·4H 2O resulted in oxidative cleavage of the C-11–C-12 double bond instead of the desired allylic oxidation of the 1-butenyl side chain. Stemofoline gave a similar result. The oxidation of more simple terminal alkenes was regioselective and gave vinyl ketones while allyl and benzyl ethers gave acrylate and benzoate esters, respectively. Allyl and benzyl ethers could be chemoselectively oxidized in the presence of a terminal alkene or benzyl group. Oxidation of an internal alkene was poorly regioselective, in contrast to the oxidation of 1-substituted cyclohexenes.