24344-85-2Relevant academic research and scientific papers
Enantiodiscrimination of racemic electrophiles by diketopiperazine enolates: asymmetric synthesis of methyl 2-amino-3-aryl-butanoates and 3-methyl-aspartates
Bull, Steven D.,Davies, Stephen G.,Epstein, Simon W.,Garner, A. Christopher,Mujtaba, Nadeam,Roberts, Paul M.,Savory, Edward D.,Smith, Andrew D.,Tamayo, Juan A.,Watkin, David J.
, p. 7911 - 7925 (2007/10/03)
Enolates of (S)-N,N′-bis-(p-methoxybenzyl)-3-iso-propylpiperazine-2,5-dione exhibit high levels of enantiodiscrimination in alkylations with (RS)-1-aryl-1-bromoethanes and (RS)-2-bromoesters, affording substituted diketopiperazines containing two new stereogenic centres in high de. Deprotection and hydrolysis of the resultant substituted diketopiperazines provides a route to the asymmetric synthesis of homochiral methyl 2-amino-3-aryl-butanoates and 3-methyl-aspartates in high de and ee.
Preparation of chiral 1-phenylethanols and bromides
Stein, Allan R.,Dawe, Robert D.,Sweet, James R.
, p. 3442 - 3448 (2007/10/02)
A fast, convenient procedure for preparing and resolving moderate to large quantities of chiral secondary alcohols is described.The general procedure involves a one-pot conversion of the ketone (various acetophenones) to the half-ester of a diacid (succinic, phthalic...) and resolution with (+)- and (-)-1-phenylethylamines.Overall yields of the enantiomeric alcohols, the variously substituted 1-phenylethanols, are generally 65-85percent with optical purities of approximately 90percent.Properties and optical rotations of a number of chiral 1-phenylethanols and of the bromides made from them are tabulated.A discussion of optical purity determinations using nmr methods is included and absolute configurations are reported.
