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Pincer and Diamine Ru and Os Diphosphane Complexes as Efficient Catalysts for the Dehydrogenation of Alcohols to Ketones
Author(s) -
Baratta Walter,
Bossi Gianluca,
Putignano Elisabetta,
Rigo Pierluigi
Publication year - 2011
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.201003022
Subject(s) - ruthenium , dehydrogenation , chemistry , pincer movement , medicinal chemistry , pyridine , catalysis , osmium , ligand (biochemistry) , ethylenediamine , pincer ligand , denticity , diamine , stereochemistry , organic chemistry , crystal structure , biochemistry , receptor
The ruthenium and osmium complexes [MCl 2 (diphosphane)(L)] (M=Ru, Os; L=bidentate amino ligand) and [MCl(CNN)(dppb)] (CNN=pincer ligand; dppb=1,4‐bis‐ (diphenylphosphino)butane), containing the N–H moiety, have been found to catalyze the acceptorless dehydrogenation of alcohols in t BuOH and in the presence of KO t Bu. The compounds trans ‐[MCl 2 (dppf)(en)] (M=Ru 7 , Os 13 ; dppf=1,1′‐bis(diphenylphosphino)ferrocene; en=ethylenediamine) display very high activity and different substrates, including cyclic and linear alcohols, are efficiently oxidized to ketones by using 0.8–0.04 mol % of catalyst. The effect of the base and the comparison of the catalytic activity of the Ru versus Os complexes are reported. The ruthenium complex 7 generally leads to a faster conversion into ketones with respect to the osmium complex 13 , which displays better activity in the dehydrogenation of 5‐en‐3β‐hydroxy steroids. The synthesis of new Ru and Os complexes [MCl 2 (PP)(L)] (PP=dppb, dppf; L=(±)‐ trans ‐1,2‐diaminocyclohexane, 2‐(aminomethyl)pyridine, and 2‐aminoethanol) of trans and cis configuration is also reported.