| Visible light has attracted more and more attention as a green and clean renewable resource.The chemical reaction promoted by photocatalysis meets the requirements of organic chemists for atom economy and green environmental protection.Nitrogen-containing heterocycles exist as unit structures in many natural products and bioactive drugs,and are very important in synthetic and medicinal chemistry.Among them,alkylamines have attracted much attention due to their diverse biological activities.Activation of the C-H bond at the nitrogen ortho position to form a C-C bond can realize the modification and transformation of the α position of nitrogen-containing heterocycles.In recent years,the photocatalytic α-alkylation of tertiary amines has been rapidly developed.There are two main types of photocatalytic tertiary amine α-position alkylation according to the intermediates: the first type is the reaction of tertiary amine compoundα-position carbon radicals under the induction of visible light.The second type refers to the cross-coupling reaction of tertiary amines being oxidized to imide ion intermediates and various nucleophiles under the induction of visible light.Organoboron reagents have unique reactivity and can be used in classical reactions such as Suzuki-Miyaura reaction,Petais coupling,etc.Organoboron reagents have received extensive attention from organic chemists in recent years,and we envision the use of organoboron reagents to achieve theα-position alkylation of tertiary amines under photocatalytic conditions.We used low-toxic and stable potassium benzyl trifluoroborate and potassium allyl trifluoroborate as nucleophiles,the green and economical dye Rose Bengal as photocatalyst,and tert-butanol peroxy or oxygen as oxidant.The benzylation and allylation of the α-position of nitrogenaryltetrahydroisoquinolines were achieved,and this method was extended to nitrogenaryltetrahydropyrrolidines.Allylation at the alpha position of the tetrahydropyrrolidine nitrogen was achieved.The method has mild conditions,green economy,and a wide range of substrates,and has broad prospects in drug synthesis. |
