Solvent-Free Stereoselective Organocatalyzed Aldol Reaction of 2-Hydroxycyclobutanone.

The stereoselective solvent-free organocatalyzed aldol reaction of 2-hydroxycyclobutanone with a selection of aromatic aldehydes has been investigated. Using L-threonine (20 mol%), deracemized aldol adducts featuring a chiral quaternary center were obtained in yields up to 72%, with syn selectivity up to 85:15 and ee up to 84%. The title compound has markedly superior reactivity to other a-hydroxy ketones. [ABSTRACT FROM AUTHOR]