Remote Control of Diastereoselectivity in Intramolecular Reactions of Chiral Allylsilanes

During investigations of cyclization reactions between chiral allylsilanes and N-acyliminium ions,
it was discovered that a suitably positioned benzyloxy group on the allylsilane component caused a reversal
in the diastereoselectivity of these reactions relative to that normally observed with alkyl-substituted
allylsilanes. This effect was subsequently observed in two other reaction types. Investigations into this
effect led to the proposal of product formation through thermodynamic control facilitated by neighboring
group interactions with a transient cationic species. This hypothesis was experimentally supported by the
isolation of an intermediate in the proposed mechanistic pathway.