Unusual cycloaddition products from the trapping of an α-oxo-sulphine (-thioketone S-oxide) with simple alkenes

Abstract

The reaction of the trimethylsilyl enol ether of 1-thiochroman-4-one 1,1-dioxide with thionyl chloride gives the corresponding α-oxo-sulphine, which has been found to give a new type of [4 + 2] cycladduct when trapped with simple electron-rich alkenes such as isobutylene and norbornene.