Practical chloromanganese-salen-catalyzed enantioselective reformatsky reaction with ketones

The first catalytic enantioselective Reformatsky reaction is realized by a controlled transmetalation of an a-iodo ester with dimethylzinc in the presence of a chloromanganese-Salen complex (20 mol%) as catalyst and 4-phenylpyridine N-oxide (25 mol%) as additive. The zinc enolate is formed under mild conditions at room temperature; it undergoes enantioselective addition to ketones. The reaction shows broad scope and moderate to good stereoselection and it allows the straightforward preparation of quaternary stereogenic centers.