Temperature-controlled bidirectional enantioselectivity in a dynamic catalyst for asymmetric hydrogenation

Asymmetric catalysis using enantiomerically pure catalysts is one of the most widely used methods for the preparation of enantiomerically pure compounds. The separate synthesis of both enantiomerically pure compounds requires tedious and time-consuming preparation of both enantiomerically pure catal...

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Bibliographic Details
Main Authors: Storch, Golo (Author) , Trapp, Oliver (Author)
Format: Article (Journal)
Language:English
Published: February 23, 2015
In: Angewandte Chemie. International edition
Year: 2015, Volume: 54, Issue: 12, Pages: 3580-3586
ISSN:1521-3773
DOI:10.1002/anie.201412098
Online Access:Verlag, lizenzpflichtig, Volltext: https://doi.org/10.1002/anie.201412098
Verlag, lizenzpflichtig, Volltext: https://onlinelibrary.wiley.com/doi/abs/10.1002/anie.201412098
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Author Notes:Golo Storch and Oliver Trapp
Description
Summary:Asymmetric catalysis using enantiomerically pure catalysts is one of the most widely used methods for the preparation of enantiomerically pure compounds. The separate synthesis of both enantiomerically pure compounds requires tedious and time-consuming preparation of both enantiomerically pure catalysts or chiral separation of the racemic products. Here, we report a stereochemically flexible diastereomeric rhodium(I) catalyst for asymmetric hydrogenations of prochiral (Z)-α-acetamidocinnamates and α-substituted acrylates, which changes its enantioselectivity depending on the temperature to produce each enantiomerically pure compound in high yield with constant high enantioselectivity over time. The same axially chiral rhodium(I) catalyst produces (R)-phenylalanine derivatives in enantiomeric ratios of up to 87:13 (R/S) at low temperature and up to 3:97 (R/S) of the corresponding S enantiomers after re-equilibration of the same catalyst at elevated temperature.
Item Description:Gesehen am 24.06.2020
Physical Description:Online Resource
ISSN:1521-3773
DOI:10.1002/anie.201412098