Metal-Catalyzed Carbenoid Reactions with Iodonium and Sulfonium Ylides

ABSTRACT: Transition metal-catalyzed decomposition of phenyliodonium and diphenylsulfonium ylides was in-vestigated with regard to application in asymmetric carbenoid reactions. Phenyliodonium ylides react in the presenceof Rh(II) catalysts with the same selectivity in inter- and intramolecular cyclopropanations as the corresponding diazocompounds, and intramolecular CH insertions proceed with identical enantioselectivities. With diphenylsulfoniumethoxycarbonylmethylide the Cu(I)-catalyzed cyclopropanation of olefins affordstrans/cis ratios and asymmetricinductions identical with those of diazo compounds, but with Rh(II) catalysts some small, although significant,selectivity variations occur, which are ascribed to coordination of diphenyl sulfide to one of the coordination sites ofthe catalyst. 1998 John Wiley & Sons, Ltd.KEYWORDS: metal-catalyzed carbenoid reactions; Iodonium ylides; Sulfonium ylides INTRODUCTION The thermal and photochemical decomposition of diazocompounds affords carbenes.