4.19 To Catalytic Asymmetric 1,2-Alkynylation

Optically active propargylic alcohols and propargylamines are highly useful and versatile building blocks. One of the most common approaches to these compounds is the catalytic asymmetric alkynylation of carbonyl compounds and imines. Various combinations of chiral ligands and metal catalysts were examined and several highly efficient asymmetric catalysts have been developed so far. Although stoichiometric amounts of metal reagents were used for this type of reaction in the earliest stages of development, direct in situ generation of a metal alkynylide species from terminal alkynes with a catalytic amount of the metal reagent is currently a major interest in organic synthesis.