638
J. Org. Chem. 1991,56,638-642
Triply Convergent, Stereospecific Alkene Formation via Peterson Olefination Anthony G. M. Barrett* and John A. Flygare Northwestern University, Evanston, Illinois 60208 Received
May
25, 1990
a-Iodo silanes 8 were prepared from a-hydroxy silanes and after halogen/metal exchange and treatment with copper(1) bromide-dimethylsulfide were coupled with acid chlorides to yield a-silyl ketones 2. Cram controlled addition with a variety of nucleophiles followed by treatment with acid or base led to either the (E)-or (2)-alkene in good overall yields from the iodide ( 4 7 4 7 % ) and with excellent stereoselectivities (>95/95/
