反应详情

Add lanthanum triflate (3.6 g, 6.16 mmol) to a solution of 2,2,2-trichloro-acetimidic acid 4-methoxybenzyl ester (52.2 g, 185 mmol) and (2R,4R)-4-hydroxypyrrolidine-1,2-dicarboxylic acid 1-tert-butyl ester 2-methyl ester (30.2 g, 123 mmol) in toluene (200 mL). Stir 2.5 h, add methanol and concentrate. Dissolve in 25:75 dichloromethane:hexanes, filter away the insolubles and purify filtrate (silica gel chromatography, eluting with dichloromethane/ethyl acetate mixtures) to give the title compound (37.85 g, 84%).

1. concentrationconcentrate
2. dissolutionDissolve in 25:75 dichloromethane
3. filtrationhexanes, filter away the insolubles
4. custompurify
5. washfiltrate (silica gel chromatography, eluting with dichloromethane/ethyl acetate mixtures)