Two kinds of the phosphorus-centered radicals produced from hydrogen atomion by 2, 2-diphenyl-1-picrylhydrazyl(DPPH were trapped by N-tert-butyl-α-phenylnitrone(PBN) and 5, 5-dimethyl-1-pyrroline N-oxide (DMPO), and ...Two kinds of the phosphorus-centered radicals produced from hydrogen atomion by 2, 2-diphenyl-1-picrylhydrazyl(DPPH were trapped by N-tert-butyl-α-phenylnitrone(PBN) and 5, 5-dimethyl-1-pyrroline N-oxide (DMPO), and investigated by means of EPR spectroscopy. The spin adducts with a characteristic hyperfine coupling constant(hfcc) caused by a phosphorus atom were observed. Based on the hfcc values caused by the phosphorus and hydrogen atoms, the con formational positions of the adducts trapped by PBN and DMPO are discussed.展开更多
The tert-butyl nitrite as a bifunctional reagent mediated radical alkene difunctionalization has emerged as a powerful strategy for synthesis of structurally diverse oxime-containing compounds.However,the phosphorus-c...The tert-butyl nitrite as a bifunctional reagent mediated radical alkene difunctionalization has emerged as a powerful strategy for synthesis of structurally diverse oxime-containing compounds.However,the phosphorus-centered radical initiated transformations remain largely elusive.Herein,a visible-lightinduced radical phosphinoyloximation of alkenes with secondary phosphine oxides and tert-butyl nitrite has been developed under photocatalyst-and metal-free conditions.This protocol features mild conditions,broad substrate scope,good functional tolerance,and operational simplicity,yielding a diverse array ofα-phosphinoyl oximes in moderate to good yields with high stereoselectivities.The photomediated homolytic cleavage of O–NO bond of tert-butyl nitrite generates the reactive tert-butoxyl radical and persistent NO radical to act as both HAT reagent and the source of oximes.展开更多
文摘Two kinds of the phosphorus-centered radicals produced from hydrogen atomion by 2, 2-diphenyl-1-picrylhydrazyl(DPPH were trapped by N-tert-butyl-α-phenylnitrone(PBN) and 5, 5-dimethyl-1-pyrroline N-oxide (DMPO), and investigated by means of EPR spectroscopy. The spin adducts with a characteristic hyperfine coupling constant(hfcc) caused by a phosphorus atom were observed. Based on the hfcc values caused by the phosphorus and hydrogen atoms, the con formational positions of the adducts trapped by PBN and DMPO are discussed.
基金the financial support from the National Natural Science Foundation of China(Nos.22201265,22201264)the China Postdoctoral Science Foundation(Nos.2022M710133,2022TQ0287)。
文摘The tert-butyl nitrite as a bifunctional reagent mediated radical alkene difunctionalization has emerged as a powerful strategy for synthesis of structurally diverse oxime-containing compounds.However,the phosphorus-centered radical initiated transformations remain largely elusive.Herein,a visible-lightinduced radical phosphinoyloximation of alkenes with secondary phosphine oxides and tert-butyl nitrite has been developed under photocatalyst-and metal-free conditions.This protocol features mild conditions,broad substrate scope,good functional tolerance,and operational simplicity,yielding a diverse array ofα-phosphinoyl oximes in moderate to good yields with high stereoselectivities.The photomediated homolytic cleavage of O–NO bond of tert-butyl nitrite generates the reactive tert-butoxyl radical and persistent NO radical to act as both HAT reagent and the source of oximes.
