Rh-Catalyzed Enantioselective Aryl C–H Bond Cyclopropylation

Herein, we disclose the discovery and development of a site-, regio-, diastereo-, and enantioselective aryl C–H bond cyclopropylation using diazomethyl hypervalent iodine reagents, styrenes, and paddlewheel dirhodium carboxylate catalysts. A key aspect of this work was the catalytic generation of a chiral Rh(II) carbene through an electrophilic aromatic substitution with chiral Rh(II) carbynoids. The strategy allows the construction of cyclopropane rings using aryl C–H bonds from aromatic feedstocks and drug molecules and promises to reach an unexplored “cyclopropanated” chemical space highly difficult to reach by current strategies.