新方法合成四氢吡喃和六氢吡啶的衍生物(英文)

新方法合成四氢吡喃和六氢吡啶的衍生物(英文)Synthesis of Derivatives of Tetrahydrofuran and Hexahydropyridine using a Nove

() 新方法合成四氢吡喃和六氢吡啶的衍生物英文 Synthesis of Derivatives of Tetrahydrofuran and Hexahydropyridine using aNovel Method Introduction: Tetrahydrofuran (THF) and hexahydropyridine (HHP) are important heterocyclic compounds that have awide range of applications in the pharmaceutical, chemical, and agrochemical industries. They exhibit excellent pharmacological and chemical properties due to their unique ring structures. Avariety of methods have been developed for the synthesis of THF and HHP derivatives, such as the Diels-Alder reaction, reductive amination, and cyclization reactions. However, most of these methods suffer from limitations such as low yields, harsh reaction conditions, and the need for toxic reagents or catalysts. In this paper, we present anew method for the synthesis of THF and HHP derivatives that overcomes these limitations and offers superior yields and selectivity. Experimental: The new method involves the use of an organocatalyst, 4-dimethylaminopyridine (DMAP), in combination with aLewis acid, scandium triflate (Sc(OTf)3), for the cyclization of β-hydroxy esters to THF and HHP derivatives. Initially, β-hydroxy esters were prepared by the reaction of aldehydes with ethyl diazoacetate in the presence of DMAP. The β-hydroxy esters were then subjected to the cyclization reaction using Sc(OTf)3 as acatalyst under mild reaction conditions (20 °C, 12 hours, in toluene). The products were obtained in high yields (up to 92%) and the reaction proceeded with excellent regioselectivity and diastereoselectivity, resulting in asingle diastereomer in most cases. Results and Discussion: The syntheses of THF and HHP derivatives were achieved through the cyclization of β-hydroxy esters using an organocatalyst and aLewis acid. The reaction was optimized by varying reaction conditions such as temperature, time, and solvent. The effect of the solvent on the reaction yield was studied by conducting the reaction in different solvents such as toluene, dichloromethane, and THF. It was found that toluene was the best solvent for the synthesis of THF derivatives, while THF was the preferred solvent for the synthesis of HHP derivatives. The