I₂-catalyzed Oxidative Coupling Synthesis Of N-phosphinyl Sulfoximines

Phosphonamide compounds represent an important class of chemical compounds due to their extensive applications in biology,agriculture and materials chemistry.However,biological activity,synthesis method and application of N-phosphinyl sulfoximines have not been reported;onl y the biological activities of phosphonamides and sulfoximines related to it have been widel y studied,and they are applied in the fields of medicine and agriculture.Hence,there is great potential for biological activit y and application of N-phosphinyl sulfoximines in the foreseeable future.The synthesis of phosphonamides by constructing N-P bonds is realized by diphenylchlorophosphine oxide,chlorophosphate or dialkylphosphine oxides and amino,diazonium and azide salts under the catai ysis of Et₃N,K₂CO₃,Pt|Pt and so on.It is important to study the synthetic process of N-phosphinyl sulfoximines.Based on the team studies on N-heteroatom bond construction and oxidative coupling reactions,discovering that N-P bond oxidative coupling wasfulfilledfromdiphenylphosphineoxideand S-methyl-S-phenylsulfoximine using H ₂O₂ as oxidant and I₂ as a catal yst.The reaction process conditions were optimized with S-methyl-S-phenylsulfoximine and diphenylphosphine as substrates.Solvent,catal yst,molar ratio of reactants a nd temperature were evaluated.The optimal process conditions for this reaction were using 10%mmol of iodine as the catalyst,one equivalent of H₂O₂ as the green oxidant,and the environmentally friendly PEG400 as the green solvent.The reaction was carried out at 60 ^oC for 24hours.In order to verify the possibilit y of scaling up the process conditions,the gram reaction under the optimal process conditions and the retention of thechiralit yoftheprocessconditionswith（S）-（+）-methylphenylsulfoximine as substrate were examined.The results showed that a good yield（71%）was obtained for the gram-grade reaction;under this process condition,the chiralit y was completel y retained without any racemization,that is,the ee value was as high as 100%ee.Finall y,we hav e synthesized 21 new N-phosphinyl sulfoximines with this process.The structures of these compounds have been strictly verified by ¹HNMR,^{1 3}CNMR,^{1 9}FNMR,^{3 1}PNMR,and HRMS.