Diastereoselective formation of aziridines from diazocarbonyl compounds and N-(O-pivaloylated d-galactosyl)benzylideneamines and ring-opening reactions with p-toluenethiol
N-Galactosyl aziridines were synthesized via BF3·OEt2 promoted addition of carbenes generated from diazocarbonyl compounds with O-pivaloylated β-D-galactosylimines in good yields and high diastereoselectivity. The ring-opening reactions with p-toluenethiol of the aziridines provided enantiometrically pure β-S-substituted phenylalanine derivatives in a highly regioselective manner.
InCl3-catalyzed asymmetric aza-Friedel–Crafts reaction of indoles with imines generated from O-pivaloylated β-d-galactosylamine
作者:Bo-Yu Li、Zhong-Jun Li、Xiang-Bao Meng
DOI:10.1016/j.carres.2010.05.025
日期:2010.8
The highly diastereoselective InCl(3)-catalyzed aza-Friedel-Craftsreaction of substituted indoles with aldimines generated from Kunz's amine was studied. The reaction afforded the desired product in good to high yields with up to >19:1 diastereoselective ratios. The O-pivaloylated beta-D-galactosyl moiety could not be cleaved under the traditional acidic conditions. It was removed successfully after
A diastereoselectivePovarov-likereaction using O-pivaloylated β-D-galactosylamine as the chiral auxiliary is described. The three-component reaction of chiral aldimines, cyclic enol ethers and nucleophiles afforded the desired products in good yields and high content of the main isomer. This procedure provides an efficient method to obtain multifunctional molecules carrying three contiguous chiral