Generation of a-Silyl Carbanions by Tin-Lithium Transmetallation

Formation of )9-Hydroxyalkylsilanes from Silyl Enol Ethers 

Silyl enol ethers have been known to undergo aldol condensations with aldehydes in the presence of Lewis acids [260, 261]. When a silyl group occupies the 

These methodologies are also effective for the synthesis of a,j8-unsaturated cyclic esters and amides [267, 268]. For example, a, 8-unsaturated y-lactone 149 is syn- 

R = alkyl, alkenyl, aryl, heteroaryl catalyst = ZnBr2, Hgl2, NaF, CsF 

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