REGIOSPECIFIC INSERTION OF [SCN](-) AND [ SECN](-) IN THE S-C-BOND AND SE-C-BOND OF TRANSITION-METAL-COORDINATED THIETANES AND SELENETANES

Pentacarbonyl(thietane)tungsten complexes react with thiocyanate, [SCN ]-, and SiO2/H2O by insertion of the CN group into a S-C bond of the f our-membered heterocycle, 1,3-migration of the pentacarbonyltungsten f ragment and protonation of the nitrogen atom to give tungsten-coordina ted thiazinthione complexes. Analogously, the reactions of a thietane tungsten complex with [SeCN]- and SiO2/H2O affords a thiazinselone com plex. A selenazinthione complex is obtained from a selenetane complex and [SCN]- (+ SiO2/H2O). The insertions are regiospecific and stereose lective. The structure of the trans-isomer of a pentacarbonyl-(thiazin thione) complex has been established by X-ray structure analysis.