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α‐Amino Acid Sulfonamides as Versatile Sulfonylation Reagents: Silver‐Catalyzed Synthesis of Coumarins and Oxindoles by Radical Cyclization
Author(s) -
Kanyiva Kyalo Stephen,
Hamada Daisuke,
Makino Sohei,
Takano Hideaki,
Shibata Takanori
Publication year - 2018
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.201800901
Subject(s) - chemistry , sulfonyl , alkene , radical , moiety , decarboxylation , catalysis , reagent , radical cyclization , combinatorial chemistry , organic chemistry , alkyl
We developed a silver‐catalyzed strategy for the generation of sulfonyl radicals from sulfonamides derived from α‐amino acids. The reaction proceeded via a decarboxylation, N–S bond cleavage and radical cyclization sequence and allows the difunctionalization of alkynes and the synthesis of 3‐sulfonylated coumarins. The reaction tolerated a broad scope of substrates and functional groups and could be extended to the synthesis of oxindoles and an isoquinolinedione by the capturing of the sulfonyl radical with an alkene moiety. Moreover, the proposed mechanism was supported experimentally and by DFT calculations.