Opposite Catalyst Selectivities Using a Common Chiral Source

Significance

Maruoka and co-worker report an asymmetric aldol reaction of cyclic ketones with substituted benzaldehydes using two different catalysts derived from one source. Switching catalyst 1 to 2 resulted in the formation of the enantiomeric aldol with the opposite absolute configuration. High anti-selectivities and enantioselectivities were obtained employing catalyst 1 or 2.