Synthesis of Enantioenriched Analogues of Novel Rh2(esp)2 Ligand
HUANG Ze-ao1,2, LU Chong-dao1
1. Xinjiang Technical Institute of Physics & Chemistry, Chinese Academy of Sciences, Urumqi 830011, China; 2. University of Chinese Academy of Science, Beijing 100049, China
Abstract:A synthetic approach toward the enantioenriched Analogues of α,α,α′,α′-tetramethyl-1,3-benzene-dipropionic acid that was the ligand of Rh2(esp)2 catalyst was reported. In this process, the chiral (R)-tert-butanesulnyl diimine derived from 1,3-benzenedialdehyde was used in the nucleophilic additions of lithium ester enolates to give two novel chiral analogues of the “esp” esters that are (Rs,Rs′,R,R′)-β-amino esters and (Rs,Rs′,R,R′,R,R′)-α,β- aziridinyl esters in yields of 96% and 65% with excellent diastereoselectivity(dr>20 :1). The structures were characterized by 1H NMR and 13C NMR.