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

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

References

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6

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.