Multi-substituted trifluoromethyl alkene construction gold-catalyzed fluoroarylation of -difluoroallenes

• Published in: Chemical science (Cambridge) 2024-03, Vol.15 (1), p.3524-3529
• Main Authors: Li, Zhi-Qiang, Tang, Hai-Jun, Wang, Zaixin, Wang, Cheng-Qiang, Feng, Chao
• Format: Article
• ISSN: 2041-6520; 2041-6539
• DOI: 10.1039/d3sc06060h

An unprecedented fluoroarylation of 1,1-difluoroallenes with a cost-effective nucleophilic fluoride reagent and aryldiazonium salts is reported. This visible light promoted gold-catalyzed reaction allows a stereo- and regioselective incorporation of both the fluorine atom and aryl group, enabling a straightforward construction of multi-substituted trifluoromethyl alkenes. Under the mild reaction conditions, a nice tolerance of diverse functional groups is achieved. The high regioselectivity for fluorine-incorporation is rationalized by considering the thermodynamic driving force of trifluoromethyl group formation, whereas the counterintuitive stereoselectivity that aryl is installed on the side of the bulkier γ-substituent is interpreted by alleviating the increasing 1,3-allylic interaction in the gold-coordinated allene intermediate en route to the product. A visible-light-promoted gold-catalyzed fluoroarylation of gem -difluoroallenes is developed. This reaction proceeds in a highly stereo- and regioselective manner and enables a facile construction of tri- and tetra-substituted trifluoromethyl alkenes.