title: Amide-Phosphonium Salt as Bifunctional Phase Transfer Catalyst for Asymmetric 1,6-Addition of Malonate Esters to para-Quinone Methides.
abstract: Asymmetric 1,6-addition of malonates to para-quinone methides has been developed by using amide-phosphonium salts derived from easily available chiral α-amino acids as bifunctional phase transfer catalysts. Stabilized para-quinone methides with various substituents on the phenyl ring were reacted with diphenyl malonates to give functionalized diaryl methines in excellent yields and high to excellent ee's. Furthermore, to show the utility of this methodology, a gram scale synthesis of an 1,6-addition adduct and its further elaboration into the key intermediate for synthesis of GPR40 agonists were also described.
authors.affiliation: Department of Chemistry, Shanghai University , 99 Shangda Road, Shanghai 200444, China.
authors.forename: Luo
authors.initials: L
authors.lastname: Ge
authors.affiliation: Department of Chemistry, Shanghai University , 99 Shangda Road, Shanghai 200444, China.
authors.forename: Xuehe
authors.initials: X
authors.lastname: Lu
authors.affiliation: Department of Chemistry, Shanghai University , 99 Shangda Road, Shanghai 200444, China.
authors.forename: Cang
authors.initials: C
authors.lastname: Cheng
authors.affiliation: Department of Chemistry, Shanghai University , 99 Shangda Road, Shanghai 200444, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Chen
authors.affiliation: Department of Chemistry, Shanghai University , 99 Shangda Road, Shanghai 200444, China.
authors.forename: Weiguo
authors.initials: W
authors.lastname: Cao
authors.affiliation: Department of Chemistry, Shanghai University , 99 Shangda Road, Shanghai 200444, China.|Key Laboratory of Synthetic Chemistry of Natural Substances, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences , 354 Fenglin Lu, Shanghai 200032, China.
authors.forename: Xiaoyu
authors.initials: X
authors.lastname: Wu
authors.affiliation: Key Laboratory of Synthetic Chemistry of Natural Substances, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences , 354 Fenglin Lu, Shanghai 200032, China.
authors.forename: Gang
authors.initials: G
authors.lastname: Zhao