CONTRASTING STERIC EFFECTS OF THE KETONES AND ALDEHYDES IN THE REACTIONS OF THE DIISOPINOCAMPHEYL ENOLBORINATES OF METHYL KETONES WITH ALDEHYDES

Treatment of the diisopinocampheylborinates of a representative series of methyl ketones with a representative series of aldehydes, both of differing steric requirements provides aldols whose enantiomeric purit ies depend on the steric requirements of both the ketones and the alde hydes. This study has shown that increasing the steric requirements of the R group in the ketones has a pernicious effect on the ee, while i ncreasing the steric requirements of the R group in tile aldehydes exe rts a beneficial effect on the ee. Copyright (C) 1996 Elsevier Science Ltd