R-Acyl thionium ions generated from R-acyl sulfoxides under Pummerer conditions are powerful electrophiles, reacting efficiently with a variety of nucleophilic species. 1-3 Bimolecular addition of these types of cations to carboncarbon double bonds is well known. 3 In the realm of natural product synthesis, most success has been achieved using intramolecular Friedel-Crafts cyclization of the Pummerer thionium ion intermediate. 4-12 ...
