Csp–Csp bond cleavage and fragment coupling: a transition metal-free “extrusion and recombination” approach towards synthesis of 1,2-diketones

Abstract

A metal-free C–C bond activation strategy of 1,3-diynes has been described via an “extrusion and recombination” approach, which delivered structurally important 1,2-diketones. This phenomenon was performed using tetra-n-butylammonium iodide (TBAI) as a catalyst and peroxide as a radical initiator and oxidant. The C–C bond activation follows sequential oxidation, extrusion of CO₂ as a byproduct and sewing of the molecular fragments to release the desired products. This protocol was elaborated towards unsymmetrical 1,2-diketones via selective generation and recombination of distinct molecular fragments. The proposed mechanism has been verified using adequate control experiments and DFT calculations.