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Photoredox Catalysis of Aromatic β‐Ketoesters for in Situ Production of Transient and Persistent Radicals for Organic Transformation
Author(s) -
Yang XiuLong,
Guo JiaDong,
Xiao Hongyan,
Feng Ke,
Chen Bin,
Tung ChenHo,
Wu LiZhu
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.201916423
Subject(s) - ketyl , radical , pinacol , photochemistry , chemistry , photoredox catalysis , photocatalysis , benzophenone , catalysis , substrate (aquarium) , combinatorial chemistry , organic chemistry , oceanography , geology
Radical formation is the initial step for conventional radical chemistry. Reported herein is a unified strategy to generate radicals in situ from aromatic β‐ketoesters by using a photocatalyst. Under visible‐light irradiation, a small amount of photocatalyst fac ‐Ir(ppy) 3 generates a transient α‐carbonyl radical and persistent ketyl radical in situ. In contrast to the well‐established approaches, neither stoichiometric external oxidant nor reductant is required for this reaction. The synthetic utility is demonstrated by pinacol coupling of ketyl radicals and benzannulation of α‐carbonyl radicals with alkynes to give a series of highly substituted 1‐naphthols in good to excellent yields. The readily available photocatalyst, mild reaction conditions, broad substrate scope, and high functional‐group tolerance make this reaction a useful synthetic tool.