Ultrasound-assisted 1,6-Hydrophosphination Of Para-Quinone Methides

Organophosphorus chemistry is an ancient field of organic research which has a history of more than a century.Organophosphorus compounds constitute a ubiquitous and important class of organic molecules.Among various organophosphorus compounds,phosphine oxides display a wide range of applicability in organic synthesis,medicinal chemistry,biochemistry,and material science.Especially,they have also been utilized as ligands in transition metal-catalyzed reactions as well as in asymmetric catalysis.Sonochemistry in the research field of “green” and sustainable chemistry has gained considerable importance in synthetic organic chemistry because it focuses on the development of novel protocols in an eco-friendly manner in a simpler and safer way.The use of ultrasonic technology for efficient chemical synthesis generally allows increasing reaction kinetics,reaction times,and product yields.The main research work contains two parts: the first is the ultrasound-assisted 1,6-hydrophosphination of 2,6-di-tert-butyl para-quinone methides with H-phosphorus oxides in the presence of inorganic base;the second is the ultrasound-assisted 1,6-hydrophosphination of propargylic alcohols with H-phosphorus oxides.In the first part of the paper,we have developed base-promoted 1,6-hydrophosphination of 2,6-di-tert-butyl para-quinone methides with H-phosphorus oxides under ultrasonic irradiation.This reaction can be finished in merely one minute and afford diarylmethyl phosphorus oxides in excellent yields(85%-99% yields).In the second part of the paper,we have studied the formation of para-quinone methide intermediates from propargylic alcohols catalyzed by Br?nsted acid,and the selective 1,6-hydrophosphination of H-phosphorus oxides with para-quinone methide intermediates under ultrasonic irradiation.This reaction can be finished in merely five minutes and afford the phosphorus oxides which contains phosphorus-substituted carbon quaternary centers in 72%-98% yields.