3.1.2.10 Reactions with Alkenes and Alkynes

The organolithium reagents undergo addition with alkenes or alkynes in an intramolecular reaction. For examples, 1-(6-bromohex-1-ynyl)benzene in the presence of butyllithium gives alkylidene cyclopentane in 60% yield. The mechanism of the reaction is not well understood.  While, N-allyl-N-benzyl-2-bromobenzamine reacts with tertiary butyllithium in the presence of (-)-sparteine to afford 1-benzyl-3-methylindoline in 87% ee (Scheme 19).

Scheme 19

Summary of the Reactions of Organolithium Reagents

Scheme 20