Synthesis of triarylmethanes by silyl radical-mediated cross-coupling of aryl fluorides and arylmethanes

Although the cross-couplings of aryl halides with diarylmethanes are mostly achieved by transition-metal catalysis, aryl fluorides are rarely used as coupling partners owing to the high inertness of C-F bonds. Herein, we describe the efficient silylboronate-mediated cross-coupling reaction of aryl fluorides with arylalkanes under transition-metal-free, room-temperature conditions. The combination of silylboronate and (KOBu)-Bu-t is critical for driving a radical process via the cleavage of C-F and C-H bonds in two appropriate coupling precursors, resulting in a cross-coupling product. This practical cross-coupling protocol is applicable to a wide variety of aryl fluorides with a C(sp(2))-F bond. This method can be extended to other coupling partners with a C(sp(3))-H bond, including diarylmethanes, diarylethanes, and monoarylalkanes. Many di- and triarylalkanes with tertiary or quaternary carbon centers can be obtained easily in moderate to high yields. We believe that the developed silylboronate-mediated cross-coupling method is a valuable contribution to C-F and C-H activation chemistry.

Automated summary

In this study, an efficient silylboronate-mediated cross-coupling reaction of aryl fluorides with arylalkanes was developed under transition-metal-free, room-temperature conditions. The method showed good adaptability to aryl fluorides with a C(sp(2))-F bond and can be extended to other coupling partners with a C(sp(3))-H bond. It provides a practical and convenient approach to obtain di- and triarylalkanes with tertiary or quaternary carbon centers.