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A Highly Active Bidentate Magnesium Catalyst for Amine‐Borane Dehydrocoupling: Kinetic and Mechanistic Studies
Author(s) -
Ried Alexander C. A.,
Taylor Laurence J.,
Geer Ana M.,
Williams Huw E. L.,
Lewis William,
Blake Alexander J.,
Kays Deborah L.
Publication year - 2019
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.201901197
Subject(s) - deprotonation , catalysis , denticity , chemistry , ligand (biochemistry) , borane , amine gas treating , magnesium , substrate (aquarium) , selectivity , homogeneous catalysis , boranes , combinatorial chemistry , photochemistry , organic chemistry , metal , ion , biochemistry , oceanography , receptor , boron , geology
A magnesium complex ( 1 ) featuring a bidentate aminopyridinato ligand is a remarkably selective catalyst for the dehydrocoupling of amine‐boranes. This reaction proceeds to completion with low catalyst loadings (1 mol %) under mild conditions (60 °C), exceeding previously reported s‐block systems in terms of selectivity, rate, and turnover number (TON). Mechanistic studies by in situ NMR analysis reveals the reaction to be first order in both catalyst and substrate. A reaction mechanism is proposed to account for these findings, with the high TON of the catalyst attributed to the bidentate nature of the ligand, which allows for reversible deprotonation of the substrate and regeneration of 1 as a stable resting state.