Visible-light-driven Phosphonoalkylation Of Alkenes

In nature,vegetation efficiently synthesizes life substrates through photosynthesis,and converts abundant renewable ligchemistry in recent years,the use of photochemistry has been able to build C-X,C-B,C-C,C-N,C-P and other chemical bonds.In addition,cyclic functional groups are widely used in various biologically active molecules and various biologically active intermediates.Among them,small rings can also be used as important reactants due to their ring tension.Therefore,scientists have paid wide attention to them.It is of great significance to develop green and efficient synthetic methods.In this paper,the phosphine alkylation of olefins was achieved under visible light-induced redox neutral conditions,ht energy into chemical energy for storage in the body.Based on natural photosynthesis,the development of artificial synthesis systems is one of the important strategies to solve future energy and environmental problems.Since the last century,Giacomo Ciamician proposed the concept of photochemistry,using light as a cleaning reagent to replace traditional chemical reagents or high-temperature and high-pressure reaction conditions,providing a green and clean path for green chemical synthesis.With the vigorous development of photoand a three-membered ring and five-membered ring（cyclopentanone）containing a phosphine skeleton were successfully constructed.The first part:using OMs/OTs as the leaving group,H-P（O）compound as the source of phosphine group,4CzIPN as the photocatalyst,Cs₂CO₃ as the base,DMF as the solvent,a series of ternary ring phosphine skeleton were constructed.The reaction was mild and efficient.The highest yield was 99%after 1.5 h at room temperature.In addition,the reaction has the advantages of wide substrate applicability and high functional group compatibility.Through our study on the mechanism,it was proved that the reaction was initiated by phosphine radical,and the aryl carbon anion intermediate was the key intermediate in the reaction,which played a decisive role in the reaction.Part two:in addition to building a series of three membered ring phosphine frameworks,we also try to build five membered ring phosphine compounds.A series of five membered cyclo（cyclopentanone）phosphine containing frameworks were successfully constructed by using ester carbonyl group as intramolecular electrophilic functional group,H-P（O）compound as the source of phosphine group,cheap organic dye4CzIPN as photocatalyst,eipea as base and DMF as solvent,About 10%by-products of phosphine hydrogenation could not be removed.To sum up,a series of cyclic phosphine containing frameworks were constructed by using cheap organic dye 4CzIPN as photocatalyst,H-P（O）compound as the source of phosphine group and DMF as solvent.It provides a new efficient method for the construction of cyclic phosphine compounds.