Palladium-Catalyzed Domino Coupling Cyclization Of 1,6-Diynes With N-heterocyclic Bromides

Many of nitrogen-containing heterocyclic molecules that occur as biologically active drugs. The development of new strategies for the assembly of collections of N-heterocyclic compounds in a rapid and efficient high-throughput manner is therefore a key activity in synthetic chemistry. So it may be extremely significant using Domino reaction to synthesis Phenanthridine compounds. In this paper, the domino reaction was investigated to Phenanthridine compounds via the C-H activation of 1,6-diynes with N-heterocyclic bromides.Use unactivated diynes with bromo(iso)quinoline in the presence of palladium catalytic system afforded different kinds of rare phenanthridine derivatives with high yield through a regioselectively C-H functionalization in one step. For example, substrate was reacted with N-heterocyclic bromides (1.2 equiv) in the presence of 2mol % of palladium(II) catalyst and 4mol % of Ph3P with of(n-Bu)3N (1.2 equiv) as an additive in DMF at 130°C. According to the results, we found the each reaction of Symmetric diynes with bromo(iso)quinoline in the presence of palladium catalytic system only afforded the main product of a heterocyclic compound,while the reaction of asymmetric 1,6 - Alkyne with 3-bromoquinoline was obtained two isomers of fused heterocyclic compounds. Substituents in the substrate are great influence at domino cyclization of the yield by the electronic effect.In this paper, the reaction of by 1,6-diynes with N-heterocyclic bromides (3-bromoquinoline,3-bromoisoquinoline,3-bromopyridine) etc, it affords 27 fused heterocyclic compounds.This paper, fused phenanthridine compounds and its derivatives were gained efficiently through Domino C-C bond formations. It would provided the good method for synthesis of many natural products, formation of the complicated structure, and preparation of the optics activity and the biological activity matters.