This work was supported financially by the Ministry of Science and Technology of China(2017YFA0206903);the National Natural Science Foundation of China(21861132004);the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB17000000);the Key Research Program of Frontier Sciences of the Chinese Academy of Sciences(QYZDY-SSW-JSC029),and K.C.Wong Education Foundation.
Photo[2+2]cycloaddition of olefins is a sought-after tool for making cyclobutanes,which are the building blocks for a wide range of biologically active molecules and natural products.However,the formation of cyclobuta...