Catalytic Asymmetric Acylation of Racemic Scondary Alcohols with Benzoyl Chloride in the Presence of a Chiral Diamine
Nonenzymatic kinetic resolution of racemic secondary alcohols is an efficient synthetic method to obtain optically active compounds in organic chemistry. Catalytic asymmetric acylation of racemic secondary alcohols has been successfully performed with achiral benzoyl chloride in the presence of only 0.3 mol% of chiral diamine (<B>3</B>) derived from (<I>S</I>)-proline, combined with 0.5 equivalent of triethylamine. This asymmetric acylation of various racemic cyclic secondary alcohols, 5, 6, or 8 membered cycloalkanols (<B>1a–1c</B>), hydroxyesters (<B>1d</B> and <B>1e</B>), and bromohydrins (<B>1f</B> and <B>1g</B>) gave the corresponding optically active benzoates (84–97% ee) and unreacted alcohols (79–95% ee). Racemic acyclic secondary alcohols (<B>1h–1j</B>) were also acylated in moderate enantioselectivity.
- Chemistry letters
Chemistry letters 1999(3), 265-266, 1999-03-05