Asymmetric syntheses of (-)-enterolactone and (7'R)-7'-hydroxyenterolactone via organocatalyzed aldol reaction.

Short syntheses of (−)-enterolactone (1a) and (7′R)-7′-hydroxyenterolactone (1b) have been achieved utilizing organocatalyzed asymmetric cross-aldol reaction of aldehydes 2 and 3 and base-mediated alkylation of lactones 5 and 4.