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Efficient and Chemoselective Reduction of Pyridines to Tetrahydropyridines and Piperidines via Rhodium‐Catalyzed Transfer Hydrogenation
Author(s) -
Wu Jianjun,
Tang Weijun,
Pettman Alan,
Xiao Jianliang
Publication year - 2013
Publication title -
advanced synthesis and catalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.541
H-Index - 155
eISSN - 1615-4169
pISSN - 1615-4150
DOI - 10.1002/adsc.201201034
Subject(s) - chemistry , pyridinium , rhodium , iodide , transfer hydrogenation , triethylamine , catalysis , formic acid , dimer , medicinal chemistry , pyridine , organic chemistry , combinatorial chemistry , ruthenium
Promoted by iodide anion the rhodium complex dimer, [Cp*RhCl 2 ] 2 , catalyzes efficiently the transfer hydrogenation of various quaternary pyridinium salts under mild conditions, affording not only piperidines but also 1,2,3,6‐tetrahydropyridines in a highly chemoselective fashion, depending on the substitution pattern at the pyridinium ring. The reduction is conducted in azeotropic formic acid/triethylamine (HCOOH‐Et 3 N) mixture at 40 °C, with catalyst loadings as low as 0.005 mol% being feasible.