Stereochemical Studies on the Addition of Allylsilanes to Aldehydes: The S E' Component

model compounds ul -1 and lk-1 have been studied to determine both the position of the silicon electrofuge and the relative orientation of the double bonds in the transition structure of the allylmetal-aldehyde condensation. the use of the deuterium label allows an unbiased assessment of the syn versus anti se' pathways. the synthesis of configurational proof of model systems ul-1 and lk-1 are discussed as well as the cyclization of the model system. cyclization of model 1 was found to proceed with high selectivity via an anti se' pathway regardless of the proximal/distal ratio for all lewis acids studied. reactions promoted by fluoride ion favored the proximal product, but both syn and anti pathways were observed.