Generation of α-Oxo Dithioesters by Dithiolanium Ylide Cycloreversion. Synthesis of 2-Acyl-3,6-dihydro-2H-thiopyrans

Article abstract of DOI:10.1021/jo01301a012

Methylation of 2-acyl-1,3-dithiolanes with CH3OSO2F affords sulfonium salts which undergo cycloreversion to α-oxo dithioesters RCOCS2CH3 (R=CH3,C6H5).In the presence of dienes (2,3-dimethyl-, 1-methyl-, or 1,3-dimethylbutadiene), good yields of 2-acyl-2-(