Copper-catalyzed Vicinal C(sp~2)-H Chalcogenation Of Benzoic Acid Derivatives Using Air As Oxidant

Selenium-containing compounds and sulfur-containing compounds are widely found in natural products,drugs,pesticides and materials.Therefore,the development of simple and effective synthetic methods for constructing C-Se bonds and C-S bonds has always been a hot spot for chemists.Many reliable strategies have been developed.However,these methods usually require some harsher conditions such as high temperature,pre-functionalized substrates,or strict anhydrous and oxygen-free conditions.Among them,the transition metal-catalyzed C-H activation strategy is favored because it avoids the pre-functionalization step of the substrate.However,this type of strategy usually faces two main problems.One is how to activate a specific C-H bond in the molecule with high selectivity to achieve its functionalization;the other is that many reactions require stoichiometric oxidants,so the development of a cheaper and greener oxidation system It is one of the challenges of this type of reaction.In this paper,8-aminoquinoline is used as the directing group,and the common diaryl diselenide or thiophenol is the source of selenium or sulfur.Under the catalysis of transition metal,the C-H functionalization of the 2-position of the oriented benzamide is realized.The main content of this article includes:(1)Study on the ortho-C(sp~2)-H selenization reaction of benzoic acid derivatives catalyzed by air oxidationUsing 8-aminoquinoline as the directing group and diaryl diselenide as the selenium source,a copper-catalyzed air as the oxidant was developed to realize the oriented benzamide 2-position C(sp2)-H bond selenization reaction.The method has mild conditions,simple operation,no need for external oxidants and additives,good substrate universality,and can obtain diaryl selenoether compounds with a medium yield.(2)Study on the ortho-C(sp~2)-H sulfurization reaction of benzoic acid derivatives catalyzed by air oxidationUsing thiophenol as the vulcanization reagent and cheap and easily available copper acetate as the catalyst,the vulcanization reaction of the 2-position C(sp~2)-H bond of benzamide is realized under air oxidation.The method is simple in operation,mild in conditions,and has a certain degree of substrate universality.