Photoexcited Copper-Catalyzed Intramolecular [2+2] Cycloaddition To Construct Bicyclo[3.2.0]heptanes

The bicyclo[3.2.0]heptane scaffold is frequently found in a wide range of bioactive molecules and plays a pivotal role in constructing key modules of these compounds. In this study, we present a strategy for the synthesis of bicyclo[3.2.0]heptanes using a copper/BINAP complex to facilitate an intramolecular [2+2] cycloaddition under visible light irradiation. This methodology offers several advantages, including the use of a cost-effective copper catalyst and the ability to achieve high yields (up to 98%) and diastereoselectivity (>20:1 dr). Our approach provides an efficient strategy for constructing the bicyclo[3.2.0]heptane framework.