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Brønsted Acid Catalyzed Friedel–Crafts‐Type Coupling and Dedinitrogenation Reactions of Vinyldiazo Compounds
Author(s) -
Zheng Haifeng,
Dong Kuiyong,
Wherritt Daniel,
Arman Hadi,
Doyle Michael P.
Publication year - 2020
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.202004328
Subject(s) - carbocation , chemistry , diazo , friedel–crafts reaction , protonation , allylic rearrangement , intramolecular force , brønsted–lowry acid–base theory , hydride , catalysis , nucleophile , electrophile , medicinal chemistry , organic chemistry , photochemistry , metal , ion
The direct Friedel–Crafts‐type coupling and dedinitrogenation reactions of vinyldiazo compounds with aromatic compounds using a metal‐free strategy are described. This Brønsted acid catalyzed method is efficient for the formation of α‐diazo β‐carbocations (vinyldiazonium ions), vinyl carbocations, and allylic or homoallylic carbocation species via vinyldiazo compounds. By choosing suitable nucleophilic reagents to selectively capture these intermediates, both trisubstituted α,β‐unsaturated esters, β‐indole‐substituted diazo esters, and dienes are obtained with good to high yields and selectivity. Experimental insights implicate a reaction mechanism involving the selective protonation of vinyldiazo compounds and the subsequent release of dinitrogen to form vinyl cations that undergo intramolecular 1,3‐ and 1,4‐ hydride transfer processes as well as fragmentation.