Diastereoselective Aldol Reaction with an Acetate Enolate: 2,6-Bis(2-isopropylphenyl)-3,5-dimethylphenol as an Extremely Effective Chiral Auxiliary
摘要:
A C2 -symmetrical phenol was used as a chiral auxiliary in the asymmetric aldol reaction of chiral acetates with various aldehydes [Eq. (a)]. The reaction proceeds readily under mild conditions to provide aldol adducts with high enantioselectivity. LDA=lithium diisopropylamide.
Asymmetric Mannich-type reactions with a chiral acetate: effect of Lewis acid on activation of aldimine
作者:Susumu Saito、Keiko Hatanaka、Hisashi Yamamoto
DOI:10.1016/s0040-4020(00)01042-5
日期:2001.1
addition. This scope was expanded to the asymmetric process using the chiral acetate, which has optically pure 2,6-bis(2-isopropylphenyl)-3,5-dimethylphenol as a chiralauxiliary with axial chirality. A Lewis acid additive is likely to have a complementary role in the pronounced activation of imine functionalities in the Mannich-type addition of the bulky chiral acetate.