Facile Construction Of CF₃-Pyridine Derivatives Via Sequential Cyclizations And One-Pot Three-Component Reaction Of ?,?-Unsaturated CF₃-Ketones

CF₃-pyridine is the core structure of many medicines,pesticides,dyes,and materials molecules.In recent years,the construction of CF₃-pyridines has attracted widespread attention from organic chemists.This thesis mainly focuses on the development of?,?-unsaturated trifluoromethyl ketones as the key building block to provide various CF₃-pyridines.In this context,we have developed two sequential cyclization reactions,thus enabling the construction of a broad range of CF₃-pyridines and CF₃-2-pyridones,which can be divided as the following two parts:(1)A one-pot transformation of?,?-unsaturated trifluoromethyl ketones with2-(phenylsulfinyl)acetamide to give trifluoromethylated 2-pyridones was realized.The reaction proceeds under mild conditions and involves multiple steps in an expeditious and controlled sequence to provide efficient access to a broad range of trifluoromethylated 2-pyridones in 35-96%yields.Moreover,further synthetic manipulations allow the routine synthesis of a diverse array of trifluoromethylated pyridines in 60-95%yields.(2)A one-pot three-component reaction of?,?-unsaturated trifluoromethyl ketones with ammonium acetate and?-dicarbonyl ester was studied.The optimized reaction conditions were established by employing(trifluoromethylsulfonyloxy)copper(I)as the Lewis acid catalyst and oxygen as the oxidant.A series of polysubstituted6-CF₃-pyridine compounds can be obtained in a yield of 24-74%under one-pot reaction conditions.