Photo-induced selenothio esterification of olefins: radical addition to vinylsilanes

Irradiation of terminal olefins or cycloalkenes with Se-phenyl (selenothioperoxy)benzoate (1) gave regioselective addition products in high yield. Vinylic silanes also gave the adducts regioselectively. The stabilization effect of the α-silyl group on the alkyl radical is discussed for photolyses in carbon tetrachloride solution. The adducts obtained from vinylsilanes were efficiently converted into vinylic selenides by action of fluoride ion. The preparation of S-allyl thiobenzoate from allylsilane is also described.