Diastereoselective synthesis of quaternary substituted thioindolines from sulfur ylide intermediates

We have examined the coupling reactions of 2-thioindoles with vinyl diazoacetates in the presence of Rh(11) catalysts. While attempted enantio- and/or diastereoselective couplings using chiral catalysts and/or chiral auxiliaries on the vinyl diazoacetate have been largely unsuccessful, substrates having resident chirality on fused thiopyrans gave thioindolines with moderate to high diastereoselectivities. (C) 2003 Elsevier Science Ltd. All rights reserved.