The Cyano Group Inserted By Free Radicals Is Inserted Into Tandem Cyclization Reactions To Synthesize Phenanthridine Derivatives

The phenanthridine skeleton is widely present in natural products as well as in drug molecules.In recent years,various methods have been developed to synthesize phenanthridine compounds.The invention includes a catalytic reaction of a transition metal palladium,nickel,or the like,a cyclization reaction of an aromatic acetylene,and a tandem addition cyclization reaction initiated by a radical.By these methods,a plurality of substituted functional phenanthrene compounds such as a trifluoromethyl group,an amino group,and an ester group are synthesized.This paper introduces a variety of methods for the synthesis of phenanthridines by free radical or non-radical reactions.Based on these studies,two different functional group substituted phenanthridines have been developed by free radical initiated addition tandem cyclization reaction.The main contents of this thesis include the following two parts:1.Construction of a 4H-pyrido[4,3,2-gh]phenanthridin-5(6H)-one skeleton via a radical cascade addition/cyclization using azo compounds as radical sources.A new radical addition/cyano insertion/homolytic aromatic substitution cascade reaction initiated by the thermal homolysis of azo compounds to access polycyclic phenanthridine derivatives has been developed.Under the catalyst and oxidant free conditions,a broad range of N-arylacrylamides are compatible to afford the desired 4H-pyrido[4,3,2-gh]phenanthridin-5(6H)-one derivatives in moderate to high yields.2.Silyl radical initiated radical cascade addition/cyclization:synthesis of silyl functionalized 4H-pyrido[493,2-gh]phenanthridin-5(6H)-ones.A cyclization cascade initiated by the addition of a silyl radical to an electron-deficient carbon-carbon double bond of N-arylacrylamides,followed by intramolecular cyano group insertion and homolytic aromatic substitution has been reported.In the presence of di-lauroyl peroxide(LPO)5 under metal-free conditions,several readily available hydrosilanes were successfully used as the source of silyl radicals and a series of silyl functionalized 4H?pyrido[4,3,2-gh]phenanthridin-5(6H)-ones were obtained in moderate to good yields.