Enantioselective conversion of meso-cyclic disulfides to chiral cyclic sulfidesvia desulfurization with chiral aminophosphines

Abstract

Enantioselective desymmetrization of meso-cyclic disulfides has been investigated on the basis of the desulfurization with chiral phosphines. Chiral tert-aminophosphines enable the desulfurization of a six-membered disulfide, cis-3,6-bis(alkoxycarbonyl)-1,2-dithiane 2, to give an enantiomerically enriched five-membered sulfide, trans-2,5-bis(alkoxycarbonyl)thiolane 5, with up to 36% ee. The desulfurization of a seven-membered disulfide, cis-3,7-bis(alkoxycarbonyl)-1,2-dithiepane 3, with chiral aminophosphines also gives a six-membered sulfide, trans-2,6-bis(alkoxycarbonyl)thiane 6, with up to 30% ee.