Oxone-DMSO Triggered Methylene Insertion and C(sp(2))-C(sp(3))-H-C(sp(2)) Bond Formation to Access Functional Bis-Heterocycles

Metal-free insertion of a methylene group was achieved for the construction of a new C(sp(2))-C(sp(3))-H-C(sp(2)) bond in order to prepare novel bis-heterocyclic scaffolds. The complete mechanistic investigations included experimental study and DFT calculations, and various symmetric and unsymmetric bispyrazoles as well as other pyrazole-based bis-heterocyclic molecules were prepared in moderate to high yields. Further modification of the bridged methylene group in the unsymmetric pyrazoles generated a chiral center to extend the scope of this method.