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Synlett 2005(17): 2682-2684  
DOI: 10.1055/s-2005-917108
LETTER
© Georg Thieme Verlag Stuttgart · New York

A Facile One-Pot Synthesis of Chiral β-Amino Esters

Tanasri Bunlaksananusorn*, Florian Rampf
Lanxess Deutschland GmbH, Fine Chemicals Research & Development, 51369 Leverkusen, Germany
Fax: +49(214)3095971322; e-Mail: tanasri.bunlaksananusorn@lanxess.com;
Further Information

Publication History

Received 16 August 2005
Publication Date:
05 October 2005 (online)

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Abstract

We report a facile one-pot synthesis of chiral β-amino ­esters via direct reductive amination of β-keto esters with ­ammonium acetate (NH4OAc) and H2 in the presence of chiral Ru-ClMeOBIPHEP catalysts using 2,2,2-trifluoroethanol (TFE) as a solvent, leading to β-amino esters in high yields with high ­enantioselectivities (up to 99% ee).

Key words

reductive amination - β-amino esters - β-keto esters - Ru-ClMeOBIPHEP catalyst

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Using solvents such as EtOH, THF, CH2Cl2 or toluene led to the recovered starting material 2a.

9

The structure of ammonium salts of β-amino esters 5 were confirmed by 1H NMR.