Lewis Acid-Mediated Friedel–Crafts-Type Formylation of Alkenes with Dichloromethyl Methyl Ether in the Presence of Pyridines

Abstract

Various alkenes are formylated with dichloromethyl methyl ether (MOMCl 2 ) by the combined use of SnCl 4 /2,6dibromopyridine (B1) or AgOTf/pyridine (B4) via Friedel−Craftstype reaction. The former reagent combination is mainly applied to α,α-diarylalkenes, while the latter one is applied not only to arylalkenes but also to some alkylalkenes. Vinyl aldehydes are exclusively obtained from alkenes that can possibly afford both allyl and vinyl aldehydes.