A One-Pot and Efficient Preparation of (S)-Benzyl 4-Hydroxy-2-Pentynoate from (S)-n-Butyn-2-Ol Using an Unusual Lithiation with n-BuLi and a Catalytic Amount of Hexamethyldisilazane

A one-pot, four-step procedure was developed for the efficient preparation of (S)-benzyl 4-hydroxy-2-pentynoate (1) from (S)-3-butyn-2-ol (2), which involved as a key step the unusual lithiation of the silyl ether 5 with n-BuLi in the presence of a catalytic amount of hexamethyldisilazane (HMDS).