Alkynes reactive carbanions

Conjugate Additions of Reactive Carbanions to Activated Alkenes and Alkynes... 

In contrast to many stable transition metal-alkyne complexes, cationic cyclopentadienyliron-alkyne complexes are reactive toward a range of nucleophiles. However, since most of the nucleophiles studied were carbanions, discussion of this chemistry is deferred to Volume 4, Chapter 3.2, Section 3.2.3. 

Although alkynes are highly reactive toward a wide range of transition metals, few instances of metal-catalyzed reactions of carbanions with alkynes are known. The most extensively developed system involves cationic iron complexes of internal alkynes. These complexes underwent alkylation by a range of carbanions to produce stable [Pg.582]

A final group of fp -carbanions which have been found to react well with at least monosubstituted epoxides are the vinylalanes formed either by direct hydroalumination or by zirconium-catalyzed car-boalumination of a terminal alkyne. Both species are insufficiently reactive to couple with epoxides and must first be converted into their corresponding ate complexes, usually by treatment with n-butylli-thium (Scheme 30). 

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