Ytterbium Acetate Promoted Asymmetric Reductive Amination: Significantly Enhanced Stereoselectivity
- 17 January 2008
- journal article
- Published by American Chemical Society (ACS) in The Journal of Organic Chemistry
- Vol. 73 (4) , 1297-1305
- https://doi.org/10.1021/jo7021235
Abstract
Reductive amination of prochiral unhindered 2-alkanones 1 with (R)- or (S)-α-MBA in the presence of Yb(OAc)3 (50−110 mol %), Raney-Ni, and hydrogen (120 psi) results in increased diastereoselectivity for the amine products 2 (80−89% de) with good yield (80−87%). The increased de is based on comparison with the best previously reported de's when using (R)- or (S)-α-MBA, regardless of the strategy employed [stepwise (isolation of ketimines) or one-pot (reductive amination)], reducing agent examined, or achiral Lewis acid or Brønsted acid examined. An in situ cis- to trans-ketimine isomerization mechanism, promoted by Yb(OAc)3, has been proposed to account for the observed increase in diastereoselectivity and suggests a new entry into the control of ketimine geometry.Keywords
This publication has 25 references indexed in Scilit:
- Key green chemistry research areas—a perspective from pharmaceutical manufacturersGreen Chemistry, 2007
- De Novo Synthesis of Troc-Protected Amines: Intermolecular Rhodium-Catalyzed C−H Amination with N-TosyloxycarbamatesOrganic Letters, 2007
- A Review on the Use of Sodium Triacetoxyborohydride in the Reductive Amination of Ketones and AldehydesOrganic Process Research & Development, 2006
- The Synthetic Versatility of AcyloxyborohydridesOrganic Process Research & Development, 2006
- Asymmetric Reductive Amination: Convenient Access to Enantioenriched Alkyl‐Alkyl or Aryl‐Alkyl Substituted α‐Chiral Primary AminesAdvanced Synthesis & Catalysis, 2006
- Organocatalysis Mediated by (Thio)urea DerivativesChemistry – A European Journal, 2006
- Asymmetric Catalysis by Chiral Hydrogen‐Bond DonorsAngewandte Chemie International Edition in English, 2006
- Highly Enantioselective Hydrogen‐Transfer Reductive Amination: Catalytic Asymmetric Synthesis of Primary AminesAngewandte Chemie International Edition in English, 2003
- Ethyl 2,4-Dioxo-4-phenylbutyrate:A Versatile Intermediate for the Large-Scale Preparation of EnantiomericallyPure α-Hydroxy and α-Amino Acid EstersSynthesis, 2003
- Enantioselective catalysis in fine chemicals productionApplied Catalysis A: General, 2001