Protodesilylation as a Stereochemical Switch: Divergent Asymmetric Synthesis from Chiral Skipped Dienes

Protodesilylation is demonstrated to function not simply as replacement of a silyl group with hydrogen but as a key switch that triggers divergent skeletal transformations. Enantioenriched silyl-substituted skipped dienes are efficiently prepared via Ru(0)-catalyzed enantioselective linear cross-dimerization of penta-1,3-dienylsilanes with acrylates, delivering the products in high yields and excellent enantiomeric excesses (up to >99% ee). Notably, subsequent protodesilylation under fluoride conditions in the presence of CuI induces intramolecular 3-exo-trig cyclization, affording vinylcyclopropanes bearing three contiguous stereogenic centers with high levels of asymmetric induction (up to 98% ee). The stereochemical outcome is strongly dependent on the E/Z geometry of the skipped diene. In contrast, protodesilylation mediated by TiCl₄ follows a distinct reaction pathway to furnish chiral 1,5-dienes with a high enantioselectivity. These results demonstrate that protodesilylation can function as a controllable strategy for divergent asymmetric synthesis from a common chiral intermediate.