Unusual Oxidation Reaction of an Overcrowded Thiagermacyclohexene Derivative

Oxidation of extremely overcrowded 1,2-thiagermacyclohex-4-ene derivatives with m-chloroperbenzoic acid resulted in competitive formation of the ring expanded 1,2,7-oxathiagermacyclohept-4-ene derivatives and the ring contracted 1,2,3oxathiagermacyclopentane derivatives. The latter reaction products are found to isomerize into the former ones very slowly at room temperature not only in solution but also in the crystalline state