Synthesis of Functionalized Cycloheptadienones Starting from Phenols and Using a Rhodium/Boron Asymmetric Catalytic System

Skeletal editing offers a unique route to assemble complex architectures from simple feedstocks that are otherwise difficult to obtain. However, the asymmetric version of skeletal editing has not been widely studied. Herein, we present a modular rhodium/boron asymmetric catalytic system that enables ring‐expansion of phenols with cyclopropenes to synthesize highly functionalized cycloheptadienones in excellent chemo‐ and regioselectivities. This unique protocol features with low‐catalyst loading, atom and step‐economies, and mild neutral reaction conditions. Isotope‐labelling experiments and DFT calculations have been conducted to reveal that boron reagent plays a vital role in the whole catalytic cycle.