Synthetically useful desulfurisation reactions of heteroaryl sulfoxide conjugate adducts

Efficient desulfurisation reactions of the conjugate addition products deri ved from 1-methyl-2-imidazolyl and 2-pyridyl sulfoxides have been achieved. Hydrodesulfurisation was effected either by reduction of the sulfoxides to sulfides, followed by treatment with Raney nickel, or more reliably by rea ction of either the sulfides or the sulfoxides with nickel boride. Pyrolyti c elimination furnished alkenes stereoselectively on heating the sulfoxides to reflux in toluene or chloroform.