화학공학소재연구정보센터
Journal of the American Chemical Society, Vol.140, No.15, 5300-5310, 2018
Copper-Catalyzed Vinylogous Aerobic Oxidation of Unsaturated Compounds with Air
A mild and operationally simple copper-catalyzed vinylogous aerobic oxidation of beta,gamma- and alpha,beta-unsaturated esters is described. This method features good yields, broad substrate scope, excellent chemo- and regioselectivity, and good functional group tolerance. This method is additionally capable of oxidizing beta,gamma- and alpha,beta-unsaturated aldehydes, ketones, amides, nitriles, and sulfones. Furthermore, the present catalytic system is suitable for bisvinylogous and trisvinylogous oxidation. Tetramethylguanidine (TMG) was found to be crucial in its role as a base, but we also speculate that it serves as a ligand to copper(II) triflate to produce the active copper(II) catalyst. Mechanistic experiments conducted suggest a plausible reaction pathway via an allylcopper(II) species. Finally, the breadth of scope and power of this methodology are demonstrated through its application to complex natural product substrates.