METAL-CATALYZED CARBENOID REACTIONS WITH IODONIUM AND SULFONIUM YLIDES

Transition metal-catalyzed decomposition of phenyliodonium and dipheny lsulfonium ylides was investigated with regard to application in asymm etric carbenoid reactions. Phenyliodonium ylides react in the presence of Rh(II) catalysts with the same selectivity in inter- and intramole cular cyclopropanations as the corresponding diazo compounds, and intr amolecular CH insertions proceed with identical enantioselectivities. With diphenylsulfonium ethoxycarbonylmethylide the Cu(I)-catalyzed cyc lopropanation of olefins affords trans/cis ratios and asymmetric induc tions identical with those of diazo compounds, but with Rh(II) catalys ts some small, although significant, selectivity variations occur, whi ch are ascribed to coordination of diphenyl sulfide to one of the coor dination sites of the catalyst. (C) 1998 John Wiley & Sons, Ltd.