Heterogeneous Raney Nickel and Cobalt Catalysts for Racemization and Dynamic Kinetic Resolution of Amines

Raney metals were studied as heterogeneous catalysts for racemization and dynamic kinetic resolution (DKR) of chiral amines, as an alternative to metals like palladium or ruthenium. Both Raney nickel and cobalt were able to selectively racemize various chiral amines with high selectivity. In the rac...

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Bibliographic Details
Published in:Advanced synthesis & catalysis Vol. 350; no. 1; pp. 113 - 121
Main Authors: Parvulescu, Andrei N., Jacobs, Pierre A., De Vos, Dirk E.
Format: Journal Article
Language:English
Published: Weinheim WILEY-VCH Verlag 04.01.2008
WILEY‐VCH Verlag
Wiley
Subjects:
Chemistry
Chemistry, Applied
Chemistry, Organic
chiral amides
chiral amines
dynamic kinetic resolution
kinetic resolution
Physical Sciences
Raney cobalt
Raney nickel
Science & Technology
PALLADIUM
chiral amines
ACYLATION
Raney nickel
RUTHENIUM
Raney cobalt
COMBINATION
resolution
ASYMMETRIC TRANSFORMATIONS
SECONDARY ALCOHOLS
TEMPERATURE
chiral amides
kinetic resolution
LIPASE
EFFICIENT
dynamic kinetic
ISSN:1615-4150, 1615-4169
Online Access:Get full text
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Summary:Raney metals were studied as heterogeneous catalysts for racemization and dynamic kinetic resolution (DKR) of chiral amines, as an alternative to metals like palladium or ruthenium. Both Raney nickel and cobalt were able to selectively racemize various chiral amines with high selectivity. In the racemization of benzylic primary amines, the minor formation of side products, e.g., secondary amines, can be suppressed by varying the hydrogen pressure. In the racemization of aliphatic amines over Raney catalysts, the selectivity is very high, with the enantiomeric amine as the sole product. DKR of racemic aliphatic amines can be performed with immobilized Candida antarctica lipase B and Raney nickel in one pot; for 2‐hexylamine, a yield of 95 % of the acetylated amide was achieved, with 97 % ee. Attention is devoted to the compatibility of the enzyme and the metal catalyst during the DKR. For benzylic primary amines, a two‐pot process is proposed in which the liquid is alternatingly shuttled between two vessels containing the solid racemization catalyst and the biocatalyst. After 4 such cycles, the amide of (R)‐1‐phenylethylamine was obtained with 94 % yield and more than 90 % ee.
Bibliography:istex:4A51D0D638DA7713FD45AEB75F00A8949A39CE14
ark:/67375/WNG-938ZX9NM-7
ArticleID:ADSC200700336
ObjectType-Article-2
SourceType-Scholarly Journals-1
ObjectType-Feature-1
content type line 23
ISSN:1615-4150
1615-4169
DOI:10.1002/adsc.200700336