The results of the aldol condensation of Evans chiral imide enolates with a series of acetophenones are reported. Activated acetophenones, such as 2, 4-difluoroacetophenone, a-chloroacetophenone, and a-chloro-and a-bromo-2, 4-difluoroacetophenone, reacted with the lithium enolate of 5 with good levels of enolate facial diastereoselectivity toward the (2R)- isomers (> 1O: l) but with low anti: syn selectivity (ca. 3: 2). Sodium and potassium ...
