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Dual Benzophenone/Copper‐Photocatalyzed Giese‐Type Alkylation of C(sp 3 )−H Bonds
Author(s) -
Abadie Baptiste,
Jardel Damien,
Pozzi Gianluca,
Toullec Patrick,
Vincent JeanMarc
Publication year - 2019
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201904111
Subject(s) - chemistry , benzophenone , polymer chemistry , photochemistry , polymerization , ketone , acrylonitrile , ketyl , methyl vinyl ketone , alkylation , radical , radical initiator , catalysis , photocatalysis , medicinal chemistry , organic chemistry , polymer , copolymer
Photocatalyzed Giese‐type alkylations of C(sp 3 )−H bonds are very attractive reactions in the context of atom‐economy in C−C bond formation. The main limitation of such reactions is that when using highly polymerizable olefin acceptors, such as unsubstituted acrylates, acrylonitrile, or methyl vinyl ketone, radical polymerization often becomes the dominant or exclusive reaction pathway. Herein, we report that the polymerization of such olefins is strongly limited or suppressed when combining the photocatalytic activity of benzophenone (BP) with a catalytic amount of Cu(OAc) 2 . Under mild and operationally simple conditions, the Giese adducts resulting from the C(sp 3 )−H functionalization of amines, alcohols, ethers, and cycloalkanes could be synthesized. Preliminary mechanistic studies have revealed that the reaction does not proceed through a radical chain, but through a dual BP/Cu photocatalytic process, in which both Cu II and low‐valent Cu I/0 species, generated in situ by reduction by the BP ketyl radical, may react with α‐keto or α‐cyano intermediate radicals, thus preventing polymerization.