2-Isopropylthioxanthone-Catalyzed Divergent Functionalization of Bicyclo[1.1.0]butanes under Visible-Light Irradiation.

1,3-Functionalized cyclobutane structural motifs are ubiquitous in natural products and pharmaceuticals. Photoinduced alkylation of bicyclo[1.1.0]butanes (BCBs) offers a step-economical strategy for accessing 1,3-functionalized cyclobutane motifs. Herein, we disclose a general and mild photocatalytic protocol of bromoallylation and alkylation of BCBs in a metal, additive-free manner by using the same photocatalyst, 2-isopropylthioxanthone, in different catalytic roles. Furthermore, the synthetic utility of these products was illustrated in the synthesis of various valuable and complex cyclobutane derivatives.