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Recent Developments in Catalytic Asymmetric Hydrogenation Employing P‐Chirogenic Diphosphine Ligands
Author(s) -
Crépy Karen V. L.,
Imamoto Tsuneo
Publication year - 2003
Publication title -
advanced synthesis and catalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.541
H-Index - 155
eISSN - 1615-4169
pISSN - 1615-4150
DOI - 10.1002/adsc.200390031
Subject(s) - chemistry , asymmetric hydrogenation , enantioselective synthesis , rhodium , catalysis , ruthenium , scope (computer science) , combinatorial chemistry , ligand (biochemistry) , mechanism (biology) , organic chemistry , receptor , biochemistry , philosophy , epistemology , computer science , programming language
Abstract Rhodium‐ and ruthenium‐catalyzed asymmetric hydrogenations reactions employing C 2 ‐symmetric chiral diphosphine ligands have a long history, and exceedingly high enantioselectivities have been reported. On the other hand, metal complexes containing P‐chirogenic, electron‐rich diphosphine ligands such as 1,2‐bis(alkylmethylphosphino)ethane (BisP*) and bis(alkylmethylphosphino)methane (MiniPHOS) have been tested only recently, and proved greatly successful. These results prompted intensive research amongst organic chemists, and the scope and limitations of the use of ligands bearing the chiral center at phosphorus atoms is presented in this review. The most recent data have been collected and summarized. In terms of ligand design, it is necessary to address an important question: “which properties are responsible for very high enantioselectivity in hydrogenation reactions?”. To this extent, a full discussion of new aspects on the mechanism, in particular the demonstration of a dihydride mechanism for enantioselective hydrogenation as opposed to the unsaturated mechanism widely accepted so far, also constitutes an important part of this review.