Subject reactions with organolithium reagents

Deprotonation of t-Bu-BisP (BH3)2 with 1.2 equivalents of s-BuLi/( )-sparteine formed a mixture of mono- and dilithiated t-Bu-BisP (BH3)2 whose - intermolecular oxidative coupling with Cu(II) afforded a mixture of tetraphosphine borane 86 and hexaphosphine borane 87. The use of ( )-sparteine may surprise the reader, as the reaction does not involve any enantioselective deprotonation. However, it was found that its presence was beneficial to activate the -BuLi, showing that ( )-sp is not only a chiral inductor, but also modifies the reactivity of the organolithium reagents. After separation by column chromatography, 86 and 87 were obtained in 26% and 14% isolated yields respectively. Tetraphosphine borane 86 was subjected to similar reactions, affording compounds 88 (29% yield) and 90 (8% yield), which contain 8... 

Preparation of 2-substituted a-Alkenes. The reaction of trimethylsilylacetone with Grignard and organolithium reagents has been employed in the synthesis of 2-substituted propenes via the formation of a /3-hydroxysilane, which is then subjected to a Peterson elimination (eq 1). It was also used to prepare, y-unsaturated esters, nitriles, and amides (eq 2). ... 

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