Recyclable gold(i)-catalyzed hydrophosphoryloxylation of alkynes or 1-haloalkynes with diphenyl phosphate

Abstract

A mesoporous SBA-15-anchored phosphine-gold(I) complex [SBA-15-Ph₂P-AuCl] was prepared via immobilization of 3-(diphenylphosphino)propyltriethoxysilane onto SBA-15, followed by reaction with Me₂SAuCl. With the use of 5 mol% SBA-15-Ph₂P-AuCl as a catalyst and 5 mol% AgPF₆ as a cocatalyst, the hydrophosphoryloxylation reaction of alkynes with diphenyl phosphate proceeded smoothly in toluene under mild conditions to deliver a wide array of kinetic enol phosphates in good to excellent yields with wide tolerance of functional groups. Besides, the regio- and stereoselective hydrophosphoryloxylation of 1-haloalkynes with diphenyl phosphate also proceeded effectively in the presence of 5 mol% SBA-15-Ph₂P-AuCl/AgOTf in toluene at 50 °C, affording (Z)-alkenyl halophosphates in high yields. This new heterogenized phosphine-gold(I) catalyst could be conveniently recovered by centrifugation of the reaction mixture and recycled several times without a significant loss of catalytic activity.