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Quinaphos and Dihydro‐Quinaphos Phosphine–Phosphoramidite Ligands for Asymmetric Hydrogenation
Author(s) -
Pullmann Thomas,
Engendahl Barthel,
Zhang Ziyun,
Hölscher Markus,
ZanottiGerosa Antonio,
Dyke Alan,
Franciò Giancarlo,
Leitner Walter
Publication year - 2010
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.201000063
Subject(s) - phosphoramidite , phosphine , asymmetric hydrogenation , diastereomer , chemistry , combinatorial chemistry , stereochemistry , catalysis , organic chemistry , enantioselective synthesis , biochemistry , dna , oligonucleotide
New derivatives of the Quinaphos ligands and the related Dihydro‐Quinaphos ligands based on the more flexible 1,2,3,4‐tetrahydroquinoline backbone have been prepared and fully characterised. A general and straightforward separation protocol was devised, which allowed for the gram‐scale isolation of the R a , S c and S a , R c diastereomers. These new phosphine–phosphoramidite ligands have been applied in the Rh‐catalysed asymmetric hydrogenation of functionalised olefins with the achievement of excellent enantioselectivities (≥99 %) in most cases and turnover frequency (TOF) values of up to ≥20 000 h −1 . These results substantiate the practical utility of readily accessible Quinaphos‐type ligands, which belong to the most active and selective category of ligands for Rh‐catalysed hydrogenation known to date.