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Direct Synthesis of Pyrazolo[5,1‐ a ]isoindoles via Intramolecular Palladium‐Catalyzed CH Bond Activation
Author(s) -
Choi Young Lok,
Lee Hyuk,
Kim Bum Tae,
Choi Kihang,
Heo JungNyoung
Publication year - 2010
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.201000260
Subject(s) - chemistry , isoindole , intramolecular force , palladium , catalysis , intermolecular force , medicinal chemistry , ring (chemistry) , isoquinoline , stereochemistry , organic chemistry , molecule
An efficient, direct synthesis of pyrazolo[5,1‐ a ]isoindoles employing a palladium‐catalyzed intramolecular CH bond activation of 1‐(2‐halobenzyl)pyrazoles has been developed. The use of lithium chloride (LiCl) was found to be essential in these reactions, to suppress further CH bond activation at the C‐3 position of pyrazolo[5,1‐ a ]isoindole, when C‐3 is unsubstituted. This protocol can be applied to the synthesis of a pyrazolo[5,1‐ a ]isoquinoline possessing a six‐membered central ring system and a fully substituted pyrazolo[5,1‐ a ]isoindole using sequential intra‐ and intermolecular CH bond activation.