Synlett 2019; 30(13): 1496-1507
DOI: 10.1055/s-0037-1611878
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© Georg Thieme Verlag Stuttgart · New York

Visible-Light Reductive Cyclization of Nonactivated Alkyl Chlorides

Miguel Claros
a   Institute of Chemical Research of Catalonia (ICIQ), Barcelona Institute of Science and Technology, Avda. Països Catalans, 16, 43007, Tarragona, Spain   Email: jlloret@iciq.es
b   University Rovira i Virgili (URV) department of physical and inorganic chemistry, C/Marcel·lí Domingo, 43007 Tarragona, Catalonia, Spain
,
Alicia Casitas
c   Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Campus de Montilivi, 17003 Girona, Catalonia, Spain   Email: alicia.casitas@udg.edu
,
Julio Lloret-Fillol
a   Institute of Chemical Research of Catalonia (ICIQ), Barcelona Institute of Science and Technology, Avda. Països Catalans, 16, 43007, Tarragona, Spain   Email: jlloret@iciq.es
d   Catalan Institution for Research and Advanced Studies (ICREA),Passeig Lluïs Companys, 23, 08010, Barcelona, Spain
› Author Affiliations
We acknowledge the financial support from the ICIQ Foundation and MINECO (CTQ2016-80038-R) to J. Ll.-F.
Further Information

Publication History

Received: 26 May 2019

Accepted after revision: 11 June 2019

Publication Date:
17 July 2019 (online)


Abstract

Nonactivated alkyl chlorides are readily available and bench-stable feedstocks; however, they exhibit an inherent chemical inertness, in part, due to their large negative reduction potentials, which have precluded their widespread use as radical precursors in visible-light photocatalysis. Herein, we highlight some recent strategies for activating challenging organic halides under light irradiation, with special emphasis in C(sp3)–halide bonds. In this line, a brief summary of the reactivity of Vitamin B12, F430 cofactor and derivatives is required to comprehend the chemistry behind our developed Cu/M (M = Co, Ni) dual catalytic system. Catalyst design has been key for developing a mild and general photoredox methodology for the intramolecular reductive cyclization of nonactivated alkyl chlorides with tethered alkenes. The cleavage of strong C(sp3)–Cl bonds is mediated by a highly nucleophilic low-valent cobalt or nickel intermediate generated by visible-light photoredox reduction employing a copper photosensitizer.