Study On The Synthesis Of Organophosphorus Compounds Based On Phosphorus-Centered Radical Difunctionalizations

Organophosphorus compounds have all along attracted considerable attention as they have broad utilities such as reagents for chemical reactions,ligands for transition metal catalysts,flame retardants,biologically active molecules and building blocks in synthetic chemistry.Compared with metal-catalyzed coupling synthesis,such as Arbuzov reaction,transformations via P-center radicals processes are powerful methods for the synthesis of organophosphorus compounds,as they provide unique routes leading to target molecules in least and concise steps.Generally,homolytic cleavage of P-H bonds serves as a major approach for the generation of P-centered radicals.Initially,BEt3 and trace air are used as the radicalinitiators which are toxic or difficult in operation.Because of the limitation of radical initiators,there is few reports about reactions involing P-centered radicals.Recently,significant progresses have been made in the development of new methods for the generation of P-center radicals.Herein,we developed five new methods for the synthesis of organophosphorus compounds via phosphono-difunctionalizations.Part 1:In conclusion,we have successfully developed a simple,highly efficient,and general method for the preparation of dialkyl 6-phenanthridinephosphonates through Mn(OAc)3-mediated radical phosphonation of 2-isocyanobiaryls under relatively mild reaction conditions.As one of its notable features,the radical process allows the direct formation of a P-C bond and the construction of a phenanthridine ring in one reaction.Moreover,a variety of useful functional groups are also tolerated,which is attributed to the mild conditions.Part 2:We have successfully developed a highly efficient and general method for the preparation of ?-hydroxyphosphonates through Mn(OAc)3-mediated radical oxidative phosphination of alkenes under relatively mild reaction conditions.This method is highly efficient and provides rapid access to a broad spectrum of?-hydroxyphosphonates in good to excellent yields.Moreover,this reaction can be effectively scaled up and the product can be conveniently obtained in a one-pot process.Part 3:We have developed Mn(OAc)3-mediated radical oxidative phosphonylation-lactonization of both terminal and internal alkenoic acids under relatively mild conditions.In particular,both ?-and ?-lactones were accessible under the standard reaction conditions bearing many functional groups in a diastereoselective manner.Part 4:The present Cu(?)-TBHP catalytic system and Mn(OAc)3-mediated radical oxidative provide a simple and inexpensive way to prepare?-phosphonotetrahydrofurans and ?-phosphonotetrahydropyrans in moderate to good yields.Importantly,this transformation would provide a new pathway for the formation of Csp3-P and Csp3-O bonds in one step.Part 5:We have developed an efficient protocol for the preparation of various 3-phosphinoylindoles via phosphinoylation-cyclization-desulfonylation of various 2-alkynylaniline derivatives with secondary phosphine oxides involving C-P and C-N bonds formation.Given that a wide range of substrates can be utilized for the cascade annulation,this simple protocol may provide a general approach to 3-phosphinoylindoles frameworks of importance in medicinal chemistry and synthetic chemistry.