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Hydrosilylative Reduction of Tertiary Amides to Amines Catalyzed by N ‐(Phosphinoaryl)anilido Complexes of Iron and Cobalt
Author(s) -
Hale Dylan J.,
Murphy Luke J.,
McDonald Robert,
Ferguson Michael J.,
Turculet Laura
Publication year - 2019
Publication title -
chemcatchem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.497
H-Index - 106
eISSN - 1867-3899
pISSN - 1867-3880
DOI - 10.1002/cctc.201900550
Subject(s) - hydrosilylation , amide , catalysis , cobalt , chemistry , alkyl , ligand (biochemistry) , medicinal chemistry , redox , organic chemistry , biochemistry , receptor
The synthesis and structural characterization of low‐coordinate Fe(II) and Co(II) complexes supported by the monoanionic P,N‐ligand N ‐(2‐dicyclohexylphosphinophenyl)‐2,6‐diisopropylanilide are described. A three‐coordinate (P,N)Fe‐hexamethyldisilazide complex ( 2 ), and four‐coordinate (P,N)Fe‐ ( 3‐Fe ) and (P,N)Co‐alkyl ( 3‐Co ) complexes were evaluated as pre‐catalysts for the hydrosilylative reduction of amides with PhSiH 3 (5 mol % pre‐catalyst, 1 equiv. PhSiH 3 , 80 °C, 1–24 h). The Fe complex 2 proved to be more broadly effective for the reduction of a variety of tertiary amide substrates, and was shown to mediate the reduction of N , N ‐dibenzylbenzamide at a loading of 1 mol %, to achieve near quantitative formation of tribenzylamine in 1 h (80 °C). Complex 2 also proved effective for the hydrosilylation of tertiary amides under ambient conditions (5 mol % Fe, 24 h), which is a unique example of room temperature amide hydrosilylation mediated by an Fe catalyst without the need for photochemical activation. Given the widespread use of amide reduction protocols in synthesis, the development of efficient Fe‐based catalysts that operate under mild conditions is an important target.