A domino reaction strategy for facile and modular construction of synthetically challenging functionalized ortho-fluoroanilines

09 July 2024, Version 1
This content is a preprint and has not undergone peer review at the time of posting.

Abstract

The selective formation of ortho-fluoroanilines, representing versatile intermediates for the pharmaceutical and fine chemical industries, relies to date on, e.g., transition-metal-catalyzed fluorination of azobenzenes, which must be pre-formed from aniline derivatives. While few efficient methods for aniline synthesis were reported, sustainable, straightforward, and selective synthesis of fluoroanilines, and in particular ortho-fluoroanilines, remains challenging. Herein, we describe a domino approach that involves the simultaneous construction of a benzene ring and the installation of both amine and fluorine groups in a single operation under metal-free conditions, starting from readily available acyclic compounds. The developed atom- and cost-efficient, highly convenient, selective, and environmentally friendly four-step domino process allows the formation of a variety of functionalized ortho-fluoroanilines with yields of up to 80% and bypasses the selectivity issues of transition-metal-catalyzed aniline fluorination reactions. Furthermore, we show that the new domino products can efficiently be utilized to synthesize fluorinated azo dye and (tetrahydro)quinazoline derivatives in a bioactive form, i.e., possessing a first-time proven micromolar antiviral activity and high selectivity (EC50 (HCMV) down to 1.9 ± 0.7 µM, CC50 up to >100 µM), under conventional and/or visible-light mediated conditions.

Keywords

domino reaction
metal-free reaction
ortho-fluoroanilines
functionalized anilines
azo dye
quinazolines
tetrahydroquinazolines
antiviral activity

Supplementary materials

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Description
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Supporting Information
Description
Materials and Methods; Experimental Procedures; Spectroscopic Data; NMR Spectra
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