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Metal‐Free Aryl Cross‐Coupling Directed by Traceless Linkers
Author(s) -
Haensch Veit G.,
Neuwirth Toni,
Steinmetzer Johannes,
Kloss Florian,
Beckert Rainer,
Gräfe Stefanie,
Kupfer Stephan,
Hertweck Christian
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.201903582
Subject(s) - aryl , chemistry , intramolecular force , combinatorial chemistry , radical , singlet state , sulfonamide , excited state , photochemistry , linker , computational chemistry , stereochemistry , organic chemistry , alkyl , physics , computer science , nuclear physics , operating system
Abstract The metal‐free, highly selective synthesis of biaryls poses a major challenge in organic synthesis. The scope and mechanism of a promising new approach to (hetero)biaryls by the photochemical fusion of aryl substituents tethered to a traceless sulfonamide linker (photosplicing) are reported. Interrogating photosplicing with varying reaction conditions and comparison of diverse synthetic probes (40 examples, including a suite of heterocycles) showed that the reaction has a surprisingly broad scope and involves neither metals nor radicals. Quantum chemical calculations revealed that the C−C bond is formed by an intramolecular photochemical process that involves an excited singlet state and traversal of a five‐membered transition state, and thus consistent ipso – ipso coupling results. These results demonstrate that photosplicing is a unique aryl cross‐coupling method in the excited state that can be applied to synthesize a broad range of biaryls.