Rhodium-Catalyzed Atroposelective C-H Fluoroallylation of Heteroarenes with gem-Difluocyclopropanes

Abstract

Atroposelective C–H bond allylation represents an efficient and sustainable strategy toward construction of axially chiral functionalized biaryls. Yet existing systems are limited in reaction patterns using olefins and allyl ethers/esters. The lack of synthetic methods is ascribed to limited mechanistic pathways underlying such transformations. Reported herein is Rh(I)-catalyzed stereoconvergent axially chiral C–H fluoroallylation of non-electron-rich arenes using racemic gem-difluorocyclopropanes as bifunctional allyl precursors, which provides biaryls integrating allyl moiety and a fluorine atom. Mechanistic studies reveal a Rh(I)/Rh(III) oxidative addition–reductive elimination cycle involving C–H activation, β-F elimination, and rapid epimerization of the chiral axis, enabling selective reductive elimination to afford the axially chiral biaryl with high regio- and enantioselectivity. A representative product exhibits circularly polarized luminescence (CPL), highlighting the potential for high-performance chiral optoelectronic applications.