Study On Phosphine/palladium-catalyzed One-Pot Synthesis Of Functionalized 6h-benzo[c]chromenes

The sequential catalytic prosess has become one of the hotest research topics and an effective method to construct important molecular framework in organic chemistry. Phosphine catalyzed addition reaction of allenes and alkynes has important applications in organic synthesis, which provides a new approach for building C-C bond, C-O bond, C-N bond, in addition, it also provides important raw materials for the synthesis of fused ring compounds. A series of compounds containing a series of aromatic hydrocarbons are synthesized by intramolecular Heck reaction. It can be applied to the synthesis of natural products and drug active molecules.1.In this paper, we choose Phosphine/Palladium-Catalyzed one-pot synthesis of functionalized 6H-benzo[c]chromenesthe as the topic. The optimal reaction conditions were found after the scanning of solvents, bases, catalysts and so on. The reaction proceeded efficiently in acetonitrile at 90 oC with PPh3 and Pd(dppf)Cl2 as catalysts, n-Bu4 NCl as a phase transfer catalyst and Na2CO3 as a base. Under these conditions, 22 different 6H-benzo[c]chromenesthe compounds were synthesized and the yields are up to 95%. among them 20 compounds are firstly reported. The structures of compounds were characterized by 1H NMR, 13 C NMR and HRMS.2.The reaction of phenol and 2-benzyl-2,3-butadienoic acid acetate compounds has been studied. The optimal reaction conditions were found after the scanning of solvents, temperatures, catalysts and so on. The reaction proceeded efficiently in benzene at 80 oC with PPh3 as catalyst. Under these conditions, 10 different ethyl ester compounds were synthesized and the yields are up to 96%. The structures of compounds were characterized by 1H NMR, 13 C NMR and HRMS.