DIASTEREOSELECTIVE OXIDATION OF LITHIUM AND CHLOROTITANOCENE ENOLATESDERIVED FROM CAMPHOR

The diastereoselective oxidation of the camphor lithium enolate 2 and the corresponding chlorotitanocene enolate 4 by various electrophilic oxidants has been examined. The diastereoselectivity of the oxygen tra nsfer depends on the metal fragment coordinated to the enolate. Thus, the chlorotitanocene enolate 4 leads to a much higher diastereomeric e xcess (de 88 to > 90%) than the corresponding lithium enolate 2 (de 12 to 60%), with the formation of exo-3-hydroxycamphor (5) as the main i somer. Copyright (C) 1996 Elsevier Science Ltd