Enantioselective synthesis of α-bromo acid derivatives and bromohydrins † from tartrate derived bromoacetals
作者:Scott A. Boyes、Alan T. Hewson
DOI:10.1039/b002106g
日期:——
Bromination of the acetals 4 derived from aryl alkyl ketones, ArCOR, and (2R,3R)-tartaric acid results in bromoacetals 5 with 78–90% de. Hydrolysis of those compounds with Ar = 4-methoxyphenyl or 3-bromo-4-methoxyphenyl results, after recrystallisation, in α-bromoketones 8 with 66–98% ee which are shown to undergo the Baeyer–Villiger oxidation to α-bromoesters 9 with minimal racemisation. α-Bromoketone
溴化 的 缩醛 4衍生自芳基烷基酮,ArCOR和(2 R,3 R)-酒石酸产生溴缩醛5的de-含量为78-90%。水解 取Ar = 4-甲氧基苯基或3-溴-4-甲氧基苯基的那些化合物 重结晶,在ee含量为66-98%的α-溴代酮8中,已显示出其经过Baeyer-Villiger氧化成α-溴代酸酯9的消旋作用极小。α-溴酮8d被证明经历了羰 减少到苏式-溴代醇15并保留立体化学。