Organocatalytic and enantioselective synthesis of beta-(hydroxyalkyl)-gamma-butyrolactones.

Organocatalytic cross-aldol reaction of methyl 4-oxobutyrate (2) and a variety of aldehydes 3 followed by reduction with NaBH(4) has provided a one-pot, general and efficient method for the synthesis of 4-(hydroxyalkyl)-gamma-butyrolactones 1 with high diastereo-(dr > 24:1) and enantioselectivity (ee > 99%).