The non-conventional hydrolysis of mixtures of diastereoisomeric α-bromo acetals, available in high yields, high diastereomeric excesses, and in large amounts, allows the synthesis and the full characterization of enantiomerically pure (2S)- and (2R)-bromoalkyl aryl ketones. The developed methodology represents the first route to enantiomerically pure 2-bromoalkyl aryl ketones of (2R) and (2S) configurations.
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