Chiral Secondary Propargylic Alcohols with Functionalized Alkynes

Significance

Chiral secondary propargylic alcohols are versatile building blocks in organic synthesis. The addition of alkynyl zinc compounds in the presence of chiral titanium complexes is a well-established route to these compounds. However, the formation of the organozinc species often requires elevated temperatures which limit the applicability to some functionalized alkynes. The authors report that by addition of a catalytic non-nucleophilic amine base such as N-methylimidazole the reaction proceeds smoothly at ambient temperature to give functionalized propargylic alcohols in good yields and ee. For a related work, see: L. Pu and co-workers Proc. Natl. Acad. Sci. U.S.A. 2004, 101, 5417.