Michael additions of oxygen and sulfur nucleophiles to 3,4-di-t-butyl-1-[(p-tolyl)sulfonylimino]-1,1-dihydrothiophene. A comparison study with 3,4-di-t-butylthiophene 1-oxide and 1,1-dioxide

The reactions of 3,4-di-t-butyl- 1-[(p-tolyl)sulfonylimino]-1,1-dihydrothio phene with RONa and RSNa furnished 2- alkoxy- and 2-alkylthio-substituted t hiophenes, respectively, through Michael adduct formation. The reaction of 3,4-di-t butylthiophene 1-oxide with RSNa gave 1,6-Michael adducts, whereas the corresponding reaction of 3,4-di-t-butylthiophene 1,1-dioxide produced a mixture of 1,4- and 1,6-adducts.