STEREOCHEMISTRY-59 NEW INSIGHTS INTO THE MECHANISM OF THE PROLINE-CATALYZED ASYMMETRIC ROBINSON CYCLIZATION; STRUCTURE OF TWO INTERMEDIATES. ASYMMETRIC DEHYDRATATION
Two sets of results give information about the mechanism of carbonyl activation by (S)-proline during asymmetric syntheses; (i) X-ray structures of two ketols produced by the proline-induced cyclization of triketones; (ii) (S)-proline-catalyzed asymmetric dehydratation of (+/-)-β ketols leading to optically active enones.