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TBAB‐Mediated Radical 5 ‐exo‐trig ipso ‐Cyclization of 2‐Arylbenzamide for the Synthesis of Spiro[cyclohexane‐1,1′‐isoindoline]‐2,5‐diene‐3′,4‐dione
Author(s) -
Qiu Guanyinsheng,
Chen ZhiFeng,
Xie Wenlin,
Zhou Hongwei
Publication year - 2019
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201900321
Subject(s) - chemistry , isoindoline , aromatization , cyclohexane , aryl , diene , radical , halogenation , radical cyclization , aryl radical , medicinal chemistry , stereochemistry , organic chemistry , catalysis , natural rubber , alkyl
A TBAB‐mediated radical 5‐ exo‐trig ipso‐ cyclization of N ‐aryl‐2‐arylbenzamide is described herein for the synthesis of spiro[cyclohexane‐1,1′‐isoindoline]‐2,5‐diene‐3′,4‐dione. The transformation proceeds regioselectively and provides the final products with high efficiency and a broad reaction scope. Mechanism studies show the use of TBAB as an additive is pivotal for the reaction. In the process, para ‐bromination of N ‐aryl group, 5‐ exo‐tri ipso ‐cyclization of N ‐aryl‐2‐arylbenzamide nitrogen radical and sequential aromatization is involved.