Asymmetric Mukaiyama−Michael Addition of Acyclic Enones Catalyzed by allo-Threonine-Derived B-Aryloxazaborolidinones
摘要:
[GRAPHICS]O-(2-Naphthoyl)-N-tosyl-L-allo-threonine B-phenyloxazaborolidinone catalyzes the asymmetric Mukaiyama-Michael addition of simple acyclic enones to give adducts of 54-85% ee, 2,6-Diisopropylphenal as an additive is demonstrated to effectively retard the undesirable Si+-catalyzed racemic pathway.