Investigations On Several Reactions Involving Nitrogen-centered Tadicals

Nitrogen radical reactions,as an important component of radical chemsitry,has been developed rapidly in recent years.Cyclobutyl ketone oxime ester was used as the precursor of radical to generate iminyl radical by single electron transfer,and the transformation can be achieved through ring-opening.The transformaitons of nitrogen radical precursors,N-F carboxamides took place in two steps.In the first step,the carboxamides nitrogen-centered radical was generated through single electron transfer.In the second step,1,5-HAT reaction generated distal carbol radical and activated C(sp3)-H bond,then the transformation of selective functional groups was achieved.The selective transformation of these two nitrogen-centered radicals was summarized and discussed in this thesis.This thesis is composed by the following two sections:In the first section,we introduced two reactions with cyclobutyl ketone oxime ester as the precursor and imine nitrogen-centered radical as the intermediate.Firstly,we introduced an efficient copper-catalysed selective C-C bond cleavage/amination of cyclobutanone oxime esters.This reaction is simple to operate and can be completed under room temperature with moderate to excellent yield.Furthermore,the reaction shows high chemo-selectivity and wide functional-group compatibility and can be easily scaled up to the gram level.Next,we described an efficient and mild copper-catalyzed selective C-C bond cleavage/sulfonylation of cycloketone oxime esters,which generated a wide range of functionalized distal cyano alkylsulfones with moderate to good yields.In the second section,we introduced two reactions with carboxamides as radical precursors and nitrogen-centered radicals as intermediate.Firstly,we described a method for site-selective intermolecular C(sp3)-H amination of carboxamides by combing transition-metal catalysis and hydrogen-atom transfer strategy.The reaction was achieved by a series of steps including favorable SET,1,5-HAT and C-N cross-coupling,then generated a series of desired products.This reaction could accommodate a wide diversity of nitrogen nucleophiles,as well as demonstrating excellent chemo-selectivity and functional-group compatibility.Next,the work on site-selective C(sp3)-H allylation of carboxamides was introduced.The reaction generated a series of allylation products in moderate to good yields.Finally,the work on site-selective C(sp3)-H azide/rhodanide of carboxamides/sulfanilamidewas introduced.