In situ Diazonium Salt Formation and Photochemical Aryl-Aryl Coupling in Continuous Flow Monitored by Inline NMR Spectroscopy.

Autor: Deckers C; Division Chemistry, Sustainable Chemical Syntheses Group, Fraunhofer Institute for Microengineering and Microsystems IMM, Carl-Zeiss-Strasse 18-20, 55129, Mainz, Germany.; Johannes Gutenberg University Mainz, Department of Chemistry, Duesbergweg 10-14, 55128, Mainz, Germany., Rehm TH; Division Chemistry, Sustainable Chemical Syntheses Group, Fraunhofer Institute for Microengineering and Microsystems IMM, Carl-Zeiss-Strasse 18-20, 55129, Mainz, Germany.
Jazyk: angličtina
Zdroj: Chemistry (Weinheim an der Bergstrasse, Germany) [Chemistry] 2024 May 28; Vol. 30 (30), pp. e202303692. Date of Electronic Publication: 2024 Apr 02.
DOI: 10.1002/chem.202303692
Abstrakt: A novel class of diazonium salts is introduced for the photochemical aryl-aryl coupling to produce (substituted) biphenyls. As common diazonium tetrafluoroborate salts fail, soluble and safe aryl diazonium trifluoroacetates are applied. In this mild synthesis route no catalysts are required to generate an aryl-radical by irradiation with UV-A light (365 nm). This reactive species undergoes direct C-H arylation at an arene, forming the product in reasonable reaction times. With the implementation of a continuous flow setup in a capillary photoreactor 13 different biphenyl derivatives are successfully synthesized. By integrating an inline 19 F-NMR benchtop spectrometer, samples are reliably quantified as the fluorine-substituents act as a probe. Here, real-time NMR spectroscopy is a perfect tool to monitor the continuously operated system, which produces fine chemicals of industrial relevance even in a multigram scale.
(© 2024 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH.)
Databáze: MEDLINE
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