Catalytic chemodivergent annulations between α-diketones and alkynyl α-diketones

Four types of unprecedented and chemodivergent reactions between α-diketones and alkynyl α-diketones have been achieved under the catalysis of phosphine and Bronsted base, respectively, leading to the rapid construction of four different classes of biologically important but synthetically challenging molecular scaffolds including 2-hydroxyfuran-3(2H)-ones, 4-hydroxy-2-oxabicyclo[2.2.1]heptan-3-ones, 1,3-diaryl cyclobutanes, and 4-(furan-2(3H)-ylidene)cyclopent-2-enones. The formation of the products includes two novel rearrangement processes, and further transformations on the products can be easily achieved to deliver value-added substances such as highly functionalized cyclopentanes. Moreover, the 2-hydroxyfuran-3(2H)-one products display promising photophysical properties such as green luminescence under UV light and aggregation-induced emission effect, showing the practical application value of this work. The great potential of α-diketones in both synthetic chemistry and material science has been unambiguously demonstrated.