Palladium/Norbornene Cooperative Catalysis: A Modular In Situ Vicinal Functionalization Strategy for Recent Developments of Carbohydrate Chemistry

The palladium/norbornene (Pd/NBE) cooperative catalysis, first identified by Catellani in 1997, provides an efficient approach for synthesizing highly functionalized aromatic compounds that are challenging to obtain through conventional methods. The developed synthetic approach integrates selective C−H bond activation with sequential reactions, allowing for the targeted functionalization of both the ortho and ipso positions of aryl halides via aryl‐norbornadiene‐palladacycle (ANP), which in turn ensures high chemoselectivity and regioselectivity of the products. It is estimated that approximately 20% of all natural products are glycosylated, with the carbohydrates linked to these compounds frequently playing a critical role in their biological activity. Currently, research in carbohydrate chemistry predominantly concentrates on polysubstitutional derivatization or vicinal functionalization strategies. However, the limited availability of 1,2‐disubstituted compounds has been scarcely investigated, and previous studies often relied on directional group assistance to achieve disubstitution. Recently, significant advancements have been achieved with Pd/NBE cooperative catalysis, an area that has gained considerable importance in carbohydrate chemistry, presenting an opportunity to inspire further research interest in Catellani reactions. In this review, we provide a comprehensive analysis of the Pd/NBE strategy within the realm of sugar chemistry, encompass early research and advancement in catalytic reactions, outline synthetic potential, highlight the significant progress made, and emphasize the most recent developments and their applications in situ vicinal functionalization of carbohydrate derivatives.