Synthesis and Photocatalytic Three-Component Ring-Opening of 3-Substituted-1-azabicyclo[1.1.0]butanes toward 3,3-Disubstituted N -Sulfonylazetidines

Aryl-substituted azetidines are found in pharmacologically active compounds; however, efficient synthetic methods to access this scaffold remain limited. Existing approaches predominantly enable the synthesis of azetidines bearing electron-rich aryl substituents. Herein, we report a new and straightforward route to 3-substituted 1-azabicyclo[1.1.0]butanes (ABBs) from commercially available tert-butyl 3-oxoazetidine-1-carboxylate in four steps. The ABBs were then applied in a three-component photocatalytic ring-opening reaction, affording 3,3-diaryl-N-sulfonylazetidines with a variety of electron-poor (hetero)arene units, a previously inaccessible chemical space. Under the optimized conditions, 29 examples of 3,3-diaryl-N-sulfonylazetidines were prepared in yields of up to 72%.