Chiral Propargyl-or Allenyl-Metal Reagents

Most of the synthetic routes to allenes utilize the reaction of propargylic compounds as electrophiles. In contrast, if the propargylic compounds serve as nucleophiles, a wide variety of substituted allenes, which are not easily accessible by the reaction of propargylic compounds with nucleophiles, are available. However, in order to synthesize enantioenriched allenes by this method, it is necessary to generate configurationally stable propargyl or allenylmetal reagents (cf. Chapter 9). 

Elimination Reactions of Allylic Compounds Having a Chiral Leaving Croup 

The (-)-sparteine-mediated lithiation of achiral propargyl carbamates with wBuLi and allene synthesis has already been described in Section 4.2.7 [84], 

Asymmetric Horner-Wadsworth-Emmons and Related Reactions 

Direct Asymmetric Synthesis of Allenes Using an External Chiral Catalyst 

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