Recent Advance on Benzofuranones: Synthesis and Transformation via C-H Functionalization

Benzofuranone is a sort of important skeleton in many fields, such as natural products, pharmaceuticals, building blocks, antioxidants and dyes. Their efficient synthesis and transformations have attracted great attentions in organic synthesis. They can be synthesized by Friedel−Crafts reaction, intramolecular dehydration ring-closing reaction and transition-metal-catalyzed reaction, etc. And their direct utilization to prepare other functional molecules enhances their further application. Due to their low pKa value and easy enolization ability, the transformation of benzofuranones via C(3)-H bond functionalization is a hot issue in the last ten years. Herein, we highlight the advances on the synthesis of benzofuranones and its transformation via C-H functionalization. Some of other transformations related to benzofuranones are also referred in this review.