The Regioselective Reaction of Atomic Hydrogen with Unsymmetric Disulfides and Sulfides

Article abstract of DOI:10.1021/jo00119a027

Unsymmetrical disulfides undergo solution phase reduction with atomic hydrogen regioselectively by displacement at the least hindered sulfur atom.The cleavage of the sulfur-sulfur bond forms mixtures of two thiol and two thiyl radicals.At the temperature at which the reactions are carried out, the thiyl radicals form symmetric disulfides by thiyl-thiyl radical coupling and not by thiyl radical displacement on the starting material.The reaction of atomic hydrogen with an unsymmetric sulfide is a cleavage that favors the formation of the most stable radical.The reaction of phenyl cyclohexyl sulfide produces benzene, cyclohexane, cyclohexyl thiol, and thiophenol.Benzene and cyclohexyl thiol produced from the cleavage of the phenyl-sulfur bond are proposed to arise from the α-scission of an intermediate formed by ipso-addition of atomic hydrogen to the benzene ring.