Catalytic stannane-fluorine activation triggered by Pd - plus Sn-F interaction

The chemistry of a-acceptor (Z-type) ligands has been attracting significant interest for some time, and the geometric and electronic structures featuring Z-type ligands have provided a profound understanding of their distinctive chemical bonds, chemical properties, and reactivities. We herein report that the coordination of Lewis acidic fluorostannane as Z-type ligands enhances their nucleophilicities, opening new opportunities for the development of Pd-catalyzed cross-coupling reaction of fluorostannanes as coupling reagents. Thanks to phosphine chelation, fluorostannane serves as a Lewis acid (Z-type ligand) toward Pd atom and withdraws electron density from the Pd center via the a*(Sn-F) orbital. Thus, the strong and polar Sn-F bond is efficiently weakened via a-donation from the Pd center. Accordingly, the F atom in fluorostannane was readily abstracted by even moderate Lewis acidic boranes, leading to the conversion of Z-type stannane to X-stannyl complexes. This key conversion enabled the catalytic arylation of fluorostannane for the first time.