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A General Approach to Deboronative Radical Chain Reactions with Pinacol Alkylboronic Esters
Author(s) -
AndréJoyaux Emy,
Kuzovlev Andrey,
Tappin Nicholas D. C.,
Renaud Philippe
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.202004012
Subject(s) - pinacol , chemistry , radical , boron , catechol , organic chemistry , aryl radical , photochemistry , medicinal chemistry , aryl , alkyl , catalysis
The generation of carbon‐centered radicals from air‐sensitive organoboron compounds through nucleohomolytic substitution at boron is a general method to generate non‐functionalized and functionalized radicals. Due to their reduced Lewis acidity, alkylboronic pinacol esters are not suitable substrates. We report their in situ conversion into alkylboronic catechol esters by boron‐transesterification with a substoichiometric amount of catechol methyl borate combined with an array of radical chain processes. This simple one‐pot radical‐chain deboronative method enables the conversion of pinacol boronic esters into iodides, bromides, chlorides, and thioethers. The process is also suitable the formation of nitriles and allylated compounds through C−C bond formation using sulfonyl radical traps. The power of combining radical and classical boron chemistry is illustrated with a modular 5‐membered ring formation using a combination of three‐component coupling and protodeboronative cyclization.