EN
Solvent effects in the L-tryptophan-catalyzed
Mannich reaction between hydroxyacetone and
glyoxylate imines have been examined. The use of a
DMSO/1-butanol (4:1 v/v) mixture as solvent at rt provided
the expected Mannich adducts in good yields, high
anti-diastereoselectivity (up to 10.3:1 anti/syn ratio) and
excellent enantioselectivities (up to >99.9% ee for the anti
isomer).