Asymmetric synthesis of 1,2-diaryl-2-amino ethanols
摘要:
A straightforward procedure for the asymmetric synthesis of 1,2-diaryl-2-amino ethanols is described. The key step relies on the diastereoselective electrophilic amination of the enolates derived from the corresponding (S,S)-(+)-pseudoephedrine arylacetamides with di-tert-butylazodicarboxylate, followed by a hydrolysis/hydrogenolysis procedure to yield alpha-amino amide derivatives with a very high degree of diastereoselection. These substrates were subsequently Subjected to a non-racemizing 1,2-addition step with several aryllithium reagents to yield the corresponding alpha-amino ketones which, upon diastereoselective reduction with NaBH4 afforded the desired beta-amino alcohols as single enantiomers with 1,2-anti relative configuration. (C) 2002 Elsevier Science Ltd. All rights reserved.
Asymmetric synthesis of 1,2-diaryl-2-amino ethanols
摘要:
A straightforward procedure for the asymmetric synthesis of 1,2-diaryl-2-amino ethanols is described. The key step relies on the diastereoselective electrophilic amination of the enolates derived from the corresponding (S,S)-(+)-pseudoephedrine arylacetamides with di-tert-butylazodicarboxylate, followed by a hydrolysis/hydrogenolysis procedure to yield alpha-amino amide derivatives with a very high degree of diastereoselection. These substrates were subsequently Subjected to a non-racemizing 1,2-addition step with several aryllithium reagents to yield the corresponding alpha-amino ketones which, upon diastereoselective reduction with NaBH4 afforded the desired beta-amino alcohols as single enantiomers with 1,2-anti relative configuration. (C) 2002 Elsevier Science Ltd. All rights reserved.