An Entry to Enantioenriched 3,3-Disubstituted Phthalides through Asymmetric Phase-Transfer-Catalyzed γ-Alkylation
作者:Marina Sicignano、Rosaria Schettini、Giovanni Pierri、Maria Leda Marino、Irene Izzo、Francesco De Riccardis、Luca Bernardi、Giorgio Della Sala
DOI:10.1021/acs.joc.0c00880
日期:2020.6.5
A novel asymmetric phase-transfer-catalyzed γ-alkylation of phthalide 3-carboxylic esters has been developed, giving access to 3,3-disubstituted phthalide derivatives, which present a chiral quaternary γ-carbon in good to excellent yields and good enantioselectivities (74–88% ee). The enantiomeric purity could be substantially enhanced to 94–95% ee by recrystallization. Both electron-withdrawing and
已开发出一种新型的不对称相转移催化的酞菁3-羧酸酯的γ-烷基化反应,从而获得了3,3-二取代的酞酸酯衍生物,该衍生物以良好的产率,良好的对映选择性和良好的手性季碳原子存在(74 –88%ee)。通过重结晶,对映体纯度可显着提高至94–95%ee。吸电子和释放电子的取代基在邻苯二甲酰亚胺核以及烷基化剂的芳族部分上均具有良好的耐受性。这种方法学使得能够在邻苯二甲酸酯γ位置引入未官能团,完全补充了先前报道的涉及官能化亲电试剂的有机催化策略,从而扩大了3,3-二取代产品的适用范围。S,13 R)-13-羟基异环celabenzine。