Reductive alkylation of bis(triflyl)methane through self-promoting formation of easily isolable 1,1-bis(triflyl)alkenes

A convenient and practical synthesis of 1,1-bis(triflyl)alkenes via self-promoting condensation of Tf2CH2 and aldehydes was developed and chemical behavior of these alkenes was investigated. Among the alkenes, easily isolable 1,1-bis(triflyl)alkadienes derived from α,β-unsaturated aldehydes could be used as useful building blocks for 1,1-bis(triflyl)alkanes. The 1,1-bis(triflyl)alkane thus obtained showed catalyst activity in the acetal forming reaction, which is a typical reaction catalyzed by Brønsted acids.