Synthesis of Cyclobutanes and Cyclobutenes by Strain-Release-Driven Ring-Opening of Bicyclo[1.1.0]butanes

Cyclobutanes and cyclobutenes exhibit intriguing structures and demonstrate significant biological activities and diverse synthetic applications. This review aims to summarize recent progress in strain-release-driven ring-opening reactions of bicyclo[1.1.0]butanes (BCBs) to synthesize these four-membered carbon rings. It outlines the strategies, regio- and stereoselectivity, the synthetic scope of reactions, and the mechanistic implications of the catalytic ring-opening process, providing a supplementary perspective to existing reviews. 1 Introduction 2 Thermally Driven Nucleophilic Ring-Opening 3 Thermally Driven Rearrangement and Isomerization Reaction 4 Light-Driven Ring-Opening 5 Transition-Metal/Lewis Acid Catalyzed Ring-Opening 6 Conclusion and Outlook