1,2,3-Trifunctionalization of α,α-disubstituted vinyl aldehydes with concomitant radical 1,2-migration of formyl group†

Compared to the well-established 1,2-difunctionalizations, the 1,2,3-trifunctionalization of alkenes has been much less developed, due to the formidable challenges in controlling site-, regio- and diastereoselectivity. Enabled by an uncommon radical-mediated 1,2-migration of carbonyls, a highly controllable 1,2,3-trifunctionalization of α,α-disubstituted vinyl aldehydes with benzoyl peroxide (BPO) as a radical initiator is successfully accomplished, providing a number of trifluoromethylated alkynyl aldehydes in moderate to good yields. Given the site-selective cleavage of allylic C–C bonds and concurrent introduction of three synthetically important functional groups, such as a trifluoromethyl motif, a formyl moiety and an alkyne, it will find widespread applications in both synthetic chemistry and the pharmaceutical industry.