Synthesis of Tertiary Silanes by Diastereoselective Rearrangement-Addition

Significance

Treatment of hydroxy-substituted silyl epoxides with Grignard reagents induced a 1,2-carbon shift to generate an unstable α-silyl aldehyde, which was trapped in situ with a range of Grignard reagents. Sterically hindered tertiary silanes, which would be difficult to generate with existing methods, were obtained with complete diastereoselectivity. The silyl epoxide is readily prepared from the propargylic alcohol by a trans-regioselective hydrosilylation catalyzed by Ru⁺ followed by a diastereoselective epoxidation.