Oxone-DMSO Triggered\nMethylene Insertion and C(sp²)−C(sp³)‑H−C(sp²) Bond Formation to Access Functional Bis‑Heterocycles

Abstract

Metal-free insertion of a methylene\ngroup was achieved for the\nconstruction of a new C­(sp²)–C­(sp³)-H–C­(sp²) bond in order to prepare novel bis-heterocyclic scaffolds.\nThe complete mechanistic investigations included experimental study\nand DFT calculations, and various symmetric and unsymmetric bis-pyrazoles\nas well as other pyrazole-based bis-heterocyclic molecules were prepared\nin moderate to high yields. Further modification of the bridged methylene\ngroup in the unsymmetric pyrazoles generated a chiral center to extend\nthe scope of this method.