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A Neutral Ru II Hydride Complex for the Regio‐ and Chemoselective Reduction of N ‐Silylpyridinium Ions
Author(s) -
Bähr Susanne,
Oestreich Martin
Publication year - 2018
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.201705899
Subject(s) - hydrosilylation , chemistry , hydride , cationic polymerization , pyridine , adduct , medicinal chemistry , catalysis , ruthenium , photochemistry , stereochemistry , polymer chemistry , organic chemistry , metal
A detailed experimental analysis of the 1,4‐selective reduction of pyridine with hydrosilanes catalyzed by a coordinatively unsaturated Ru II thiolate complex is reported. The previously suggested intermediates, N ‐silylpyridinium ions and a neutral Ru II hydride, have been independently synthesized and do indeed participate in the catalytic cycle. The resting state is not the cationic Ru II complex initially used as the catalyst but its pyridine‐coordinated congener. All Ru II complexes, including the one resulting from hydrosilane activation, are in equilibrium with each other. The N ‐silylated 1,4‐dihydropyridine together with the cationic Ru II complex convert back into the corresponding N ‐silylpyridinium ion and the neutral Ru II hydride (retro‐hydrosilylation), followed by further backward reaction into the hydrosilane and the pyridine adduct of the cationic complex. These steps prove the overall reversibility of the transformation.