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Palladium‐Catalyzed sp 2 C−H Arylation of Azoarenes with Arylhydrazines
Author(s) -
Li Mingyang,
Ye Yong
Publication year - 2015
Publication title -
chemcatchem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.497
H-Index - 106
eISSN - 1867-3899
pISSN - 1867-3880
DOI - 10.1002/cctc.201500575
Subject(s) - chemistry , catalysis , palladium , azobenzene , phenylhydrazine , aryl , yield (engineering) , reagent , reductive elimination , transition metal , medicinal chemistry , combinatorial chemistry , photochemistry , polymer chemistry , organic chemistry , molecule , alkyl , materials science , metallurgy
Transition‐metal‐catalyzed direct functionalization of C−H bonds is important for new compound synthesis, but usually needs special reagents and harsh conditions. With the aid of an azo directing group, the palladium‐catalyzed ortho ‐sp 2 C−H bond activation of azoarenes with hydrazines has been explored. In the reaction, the Pd catalyst reacts with azobenzene to form a palladacyclic intermediate, which reacts with a phenyl radical generated from phenylhydrazine under heating and oxygen to produce a Pd IV or Pd III intermediate. This finally undergoes reductive elimination to give the ortho ‐arylated products with the release of the Pd II catalyst. This reaction provides a novel access to ortho ‐aryl azoarenes under mild conditions in high yield.