The First Modular Route to Core-Chiral Bispidine Ligands and Their Application in Enantioselective Copper(II)-Catalyzed Henry Reactions
作者:Dagmar Scharnagel、Andreas Müller、Felix Prause、Martin Eck、Jessica Goller、Wolfgang Milius、Matthias Breuning
DOI:10.1002/chem.201502090
日期:2015.8.24
2‐endo‐substituted and 2‐endo,N‐fused bi‐ and tricyclic bispidines. The new diamines were evaluated as the chiral ligands in asymmetric Henry reactions. Excellent enantioselectivities of up to 99 % ee and good diastereomeric ratios of up to 86:14 were reached with a copper(II) complex modified by a 2‐endo,N‐(3,3‐dimethylpyrrolidine)‐annelated bispidine. Its performance is superior to that of the well‐known bispidines
通过采用“由内而外”的策略,首次实现了核心手性联吡啶的模块化和灵活合成。关键中间体是NBoc活化的联吡啶二内酰胺,它是通过手性修饰的β-氨基酸和2-(乙酰氧基甲基)丙烯腈以对映体纯的形式通过五个步骤构建的,收率为48%。一个简单的加法-还原协议所允许的高度内切-选择性取代基的引入,因此,一个快速和可变访问2-内型-取代的和2-内型,Ñ -融合二和三环bispidines。在不对称的亨利反应中,将新的二胺评估为手性配体。高达99%ee的出色对映选择性和高达86:14的非对映体良好比率与铜(II)配合物由2-改性达到内,Ñ(3,3-二甲基吡咯烷)-annelated bispidine - 。它的性能优于众所周知的双吡啶(-)-天冬氨酸和(+)-天冬氨酸替代品。