Modular Synthesis of Tetrasubstituted Thioallenoates via the Tandem Wolff Rearrangement/C–S Bond Insertion Reaction of Alkynyl Diazoketones and N,S -Acetals

Here, we present an approach for one-pot synthesis of tetrasubstituted thioallenoates via the addition of N,S-acetals to alkynyl ketenes generated in situ from alkynyl diazoalkyl ketones under photoirradiation. This reaction proceeds through a Wolff rearrangement/nucleophilic addition/1,5-migration cascade pathway, in which the alkynyl diazoalkyl ketones act as C4 synthons. This protocol is advantageous because of its mild conditions, short reaction time, broad substrate scope, and scale-up reaction.