Reaction of silyl thioketones with lithium diethylphosphite: first observation of Thia-Brook rearrangement

Reaction of silyl thioketone 7 with lithium diethylphosphite at - 98 degree s C afforded a S-attack product 8 and formal C-attack products 10 and 11, w hich were formed by S-to-C: migration of the phosphoryl group in the S-addu ct followed by C-to-S migration of the silyl group (Thia-Brook rearrangemen t), in a ratio depending on the conditions. The relative facility of the Th ia-Brook rearrangement was compared with that of the Brook rearrangement us ing the (t-butyldimethylsilyl)diphenylmethyl derivatives 22 and 23. (C) 200 0 Elsevier Science S.A. All rights reserved.