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Hydrogenation of Imines Catalyzed by 2‐(Aminomethyl)pyridine‐Based Ruthenium and Osmium Complexes
Author(s) -
Solinas Maurizio,
Sechi Barbara,
Baldino Salvatore,
Baratta Walter,
Chelucci Giorgio
Publication year - 2016
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.201600548
Subject(s) - osmium , ruthenium , methylamine , chemistry , medicinal chemistry , pincer movement , catalysis , pyridine , aryl , alkyl , organic chemistry
CNN pincer ruthenium(II) and osmium(II) complexes of general formula RuCl(CNN)(dppb) ( 1 a ‐ c ) and OsCl(CNN)(dppb) ( 2 a,b ) (dppb=Ph 2 P(CH 2 ) 4 PPh 2 , HCNN=[6‐( p ‐tolyl)‐2‐pyridyl]methylamine ( 4 ), N ‐methyl‐[6‐( p ‐tolyl)‐2‐pyridyl]methylamine ( 7 ) and N,N ‐dimethyl‐[6‐( p ‐tolyl)‐2‐pyridyl]methylamine ( 8 )) were prepared and assessed as catalysts in the hydrogenation of a variety of imines. Among the examined complexes, the Ru‐complex 1 a , RuCl( 4 )(dppb), showed the best activity, reducing N ‐aryl and N ‐alkyl imines to the related amines in high yields (up to 100 %) with a catalyst loading of 0.1‐1 mol% and under mild conditions (5 atm H 2 , 40‐70 °C). The Os‐complexes exhibited a lower activity than their ruthenium analogues. Despite this, the Os‐complex 2 a , OsCl( 4 )(dppb), was successful in the reduction of N ‐benzylideneaniline at 70 °C, affording a rare example of application of osmium complexes in the catalytic hydrogenation of imines.