Umpolung Synthesis of Selenoesters and Telluroesters via the Photoinduced Coupling of Acylsilanes with Electrophilic Chalcogen Reagents.

A novel synthesis of selenoesters and telluroesters based on the reactions of nucleophilic siloxycarbenes, which were generated by the visible-light-induced isomerization of the corresponding aroyl-, heteroaroyl-, or alkenoylsilanes, with electrophilic chalcogen reagents was developed. The use of appropriate selenides or ditellurides/Lewis acids enabled the coupling at temperatures below ambient temperature with a broad substrate scope and high functional-group tolerance. To the best of our knowledge, this is the first example of a synthetic method for selenoesters and telluroesters involving the combination of an acylanion equivalent and cationic chalcogen synthons.