Studies On Phosphorylation Reactions Based On Air-Initiated Phosphoryl Radicals

Organophosphorus compounds are an important part of organic compounds.As functional molecules,they are widely used in ligands,organic synthesis,luminescent materials,medicine,pesticides,flame retardant and extractants.The traditional synthesis method of organophosphorus compounds usually relies on the conversion of toxic organic halides or the harsh reaction conditions of anhydrous and oxygen-free,and has the shortcomings of narrow substrate application range,low reaction efficiency and poor atomic economy,which does not conform to the current green chemistry basic requirements.Phosphoryl radical reaction has developed rapidly in recent years,providing an efficient and convenient way for the synthesis of organophosphorus compounds,and has become a hot spot in the study of organophosphorus chemistry.However,the initiation of phosphoryl radical often requires the use of transition metals or strong oxidants.Therefore,research on the reaction of initiating phosphoryl radical under green and mild conditions needs to be carried out urgently.The research in this paper is based on the phosphoryl radical reaction initiated by air,which realizes the efficient construction of P—O,P—N and C—P bonds under mild conditions.This research content is divided into the following two parts:(1)In the first part of the work,air was used as a green oxidant to initiate the reaction of phosphoryl radical,which greatly improved the Atherton-Todd reaction.In this reaction,the P(O)H compound undergoes autoxidation in air to generate phosphoryl radical.Subsequently,the highly active phosphoryl radical grab the chlorine atoms in the chloroform to generate phosphoryl chloride on site,and the dichloromethyl radical produced at the same time can further grab the hydrogen atoms in the P(O)H compound to produce the phosphoryl radical.Finally,phosphoryl chloride reacts with nucleophile reagent to generate various phosphorylation products.Compared with the traditional Atherton-Todd reaction,this method has the following advantages:1)Replace the highly toxic carbon tetrachloride(solvent)with1 equivalent of less toxic chloroform;2)Use environmentally friendly air as the phosphoryl radical initiator;3)A variety of suitable reaction solvents;4)A wide range of substrates;5)The reaction scale is 10 gram.(2)The second part of the work also uses the phosphoryl radical reaction directly initiated by air to achieve the phosphorylation of the 1,3-dicarbonyl compound C(sp~3)—H bond.In this reaction,cheap ferrous sulfate is used as a Lewis acid to generate stable enol intermediates with 1,3-dicarbonyl compounds on site,and the carbon-carbon double bond of enol is added by phosphoryl radical initiated by air.The C—P bond is constructed,and the importantβ-ketophosphonates is finally generated through the cleavage of the C—C bond.This reaction avoids the use of expensive transition metal catalysts and excessive strong oxidants,uses cheap and low-toxic iron as a catalyst and air as a green oxidant,and provides a green and efficient new method for the synthesis ofβ-ketophosphonates.