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Mechanism‐Based Enantiodivergence in Manganese Reduction Catalysis: A Chiral Pincer Complex for the Highly Enantioselective Hydroboration of Ketones
Author(s) -
Vasilenko Vladislav,
Blasius Clemens K.,
Wadepohl Hubert,
Gade Lutz H.
Publication year - 2017
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201704184
Subject(s) - hydroboration , chemistry , enantioselective synthesis , isoindoline , ketone , selectivity , catalysis , alkyl , manganese , pincer ligand , combinatorial chemistry , hydride , ligand (biochemistry) , organic chemistry , pincer movement , medicinal chemistry , metal , biochemistry , receptor
A manganese alkyl complex containing a chiral bis(oxazolinyl‐methylidene)isoindoline pincer ligand is a precatalyst for a catalytic system of unprecedented activity and selectivity in the enantioselective hydroboration of ketones, thus producing preparatively useful chiral alcohols in excellent yields with up to greater than 99 % ee . It is applicable for both aryl alkyl and dialkyl ketone reduction under mild reaction conditions (TOF >450 h −1 at −40 °C). The earth‐abundant base‐metal catalyst operates at very low catalyst loadings (as low as 0.1 mol %) and with a high level of functional‐group tolerance. There is evidence for the existence of two distinct mechanistic pathways for manganese‐catalyzed hydride transfer and their role for enantiocontrol in the selectivity‐determining step is presented.