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Rhodium‐Catalyzed Silylation of Aromatic Carbon–Hydrogen Bonds in 2‐Arylpyridines with Disilane
Author(s) -
Tobisu Mamoru,
Ano Yusuke,
Chatani Naoto
Publication year - 2008
Publication title -
chemistry – an asian journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.18
H-Index - 106
eISSN - 1861-471X
pISSN - 1861-4728
DOI - 10.1002/asia.200800090
Subject(s) - chemistry , silylation , disilane , rhodium , trimethylsilyl , pyridine , medicinal chemistry , catalysis , regioselectivity , organic chemistry , alkoxy group , alkyl , silane
The rhodium(I)‐catalyzed regioselective silylation of the ortho carbon–hydrogen bond in 2‐arylpyridines with disilane is described. For example, the reaction of 2‐(2‐methylphenyl)pyridine with 2 equivalents of hexamethyldisilane in the presence of 5 mol % [RhCl(cod)] 2 (cod=1,5‐cyclooctadiene) in o ‐xylene at 130 °C for 15 h gave 2‐[2‐methyl‐6‐(trimethylsilyl)phenyl]pyridine in 86 % yield. In contrast to silylation with hydrosilanes, hydrogen acceptors are not required to achieve high conversion. A variety of substituents, including alkoxy, amine, ester, and fluorinated groups, are compatible with this catalysis. When substrates containing two ortho CH bonds are used, monosilylated products are obtained selectively by utilizing the 3‐methyl‐2‐pyridyl group as a directing group.