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Fast Racemisation of Chiral Amines and Alcohols by Using Cationic Half‐Sandwich Ruthena‐ and Iridacycle Catalysts
Author(s) -
Jerphag Thomas,
Gayet Arnaud J. A.,
Berthiol Florian,
Ritleng Vincent,
Mršić Nataša,
Meetsma Auke,
Pfeffer Michel,
Minnaard Adriaan J.,
Feringa Ben L.,
de Vries Johannes G.
Publication year - 2009
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200902103
Subject(s) - enantiopure drug , kinetic resolution , cationic polymerization , catalysis , chemistry , enantiomer , lipase , yield (engineering) , enantiomeric excess , organic chemistry , enantioselective synthesis , enzyme , materials science , metallurgy
The lipase‐catalysed resolution of alcohols and amines yields only 50 % of the desired enantiopure product. However, addition of a racemisation catalyst leads to 100 % yield in what is called a dynamic kinetic resolution (DKR). There is a need for new racemisation catalysts that are fast and compatible with the conditions of the enzymatic reaction. We show that cationic half‐sandwich ruthena‐ and iridacycle complexes are highly active and efficient in the racemisation of chiral alcohols and amines. Upon activation with base, these complexes are able to selectively racemise alcohols, whereas the non‐activated complexes are selective catalysts for the racemisation of amines. We have applied the iridacycles in the DKR of racemic β‐chloroalcohols to produce chiral epoxides in a biphasic system in good yields and high ee ( ee =enantiomeric excess).