Abstract

DENMARK, Scott E.  and  ALMSTEAD, Neil G.. Stereochemical Studies on the Addition of Allylsilanes to Aldehydes: The S_E' Component. J. Mex. Chem. Soc [online]. 2009, vol.53, n.3, pp.174-192. ISSN 1870-249X.

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 S_E' 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 S_E' 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.

Keywords : Allyllsilanes; Addition to Aldehides; Condensation Reaction; Cyclization; Stereochemistry.