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Catalyst‐Controlled Regiodivergent Alkyne Insertion in the Context of C−H Activation and Diels–Alder Reactions: Synthesis of Fused and Bridged Cycles
Author(s) -
Zhou Xukai,
Pan Yupeng,
Li Xingwei
Publication year - 2017
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201704036
Subject(s) - alkyne , intramolecular force , chemistry , rhodium , regioselectivity , catalysis , steric effects , context (archaeology) , migratory insertion , medicinal chemistry , stereochemistry , selectivity , cobalt , organic chemistry , paleontology , biology
Rhodium(III)‐ and cobalt(III)‐catalyzed C−H activation of indoles and coupling with 1,6‐enynes is discussed. Under rhodium(III) catalysis, the alkyne insertion follows 2,1‐regioselectivity with a subsequent type‐I intramolecular Diels–Alder reaction (IMDA) to afford [6,5]‐fused cycles. When catalyzed by the cobalt(III) congener, 1,2‐insertion of the alkyne is preferred, and followed by a rare type‐II IMDA, thus leading to bridged [3,3,1]‐cycles. This selectivity of the alkyne insertion was mainly tuned by the steric sensitivity of the catalyst.