950520-99-7Relevant academic research and scientific papers
Ytterbium acetate promoted asymmetric reductive amination: Significantly enhanced stereoselectivity
Nugent, Thomas C.,El-Shazly, Mohamed,Wakchaure, Vijay N.
, p. 1297 - 1305 (2008)
(Chemical Equation Presented) 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 Bronsted 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.
An investigation of the observed, but counterintuitive, stereoselectivity noted during chiral amine synthesis via N-chiral-ketimines
Nugent, Thomas C.,Williams, Richard Vaughan,Dragan, Andrei,Mendez, Alejandro Alvarado,Iosub, Andrei V.
supporting information, p. 2103 - 2112 (2013/11/19)
The default explanation for good to high diastereomeric excess when reducing N-chiral imines possessing only mediocre cis/transimine ratios (>15% cis-imine) has invariably been in situ cis-to-trans isomerization before reduction; but until now no study un
SYNTHESIS OF AMINES WITH YTTERBIUM LEWIS ACIDS
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Page/Page column 25, (2008/06/13)
The invention relates to methods for producing primary, secondary, and tertiary amines and the corresponding enantiopure or enantioenriched primary or secondary amine products from secondary or tertiary amine diastereomers.
