Palladium-catalyzed Hydroaminocarbonylation Of Alkynes With Ammonium Chloride

Amides are not only recognized as fundamental structural motifs in myriad of natural products,pharmaceuticals,functional materials,and agrochemicals,but also serve as attractive precursors in a variety of organic transformations especially the?,?-unsaturated primary amides.Thus how to synthesis?,?-unsaturated primary amides with high efficiency and economically is of great significance.One of the most promisingmethodstoward?,?-unsaturatedprimaryamidesis hydroaminocarbonylation of simple alkynes with amines in the presence of CO,which represents an ideal and atom economic approach toward amides without formation of any by-products.Despite all these achievements,many important research questions and challenges remain exist such as the harsh reaction conditions,suffering from poor chemoselectivity and the lack of transformation toward primary acrylamides cause the frequently used nitrogen source for hydroaminocarbonylation of simple alkynes are either primary amines or secondary amines.However,till now there has been tiny examples toward?,?-unsaturated primary amides,among which are traditional stoichiometric reactions from nitrile or acyl chloride that could lead to a big amount of waste.Therefore,an effective and economical catalytic method is urgently needed.The hydroaminocarbonylation reactions were conducted in the presence of 20 atm of CO at 80°C.Pd?PPh₃?₄ has been identified as catalyst?5 mol%?,DPEphos was used as ligand?6 mol%?and hydroxylamine hydrochloride was used as amine source?150mol%?.The yields of desired products can be up to 92%with excellent regioselectivity?B:L>20:1?.Compared to previous methods,there is a good adaptability for substrate under relative mild reaction conditions and the amine source is cheap and easy to gain.