Studies On Cyclization Reactions Based On Sulfoximine-directed Activation Of CH/NH Bonds

Transition-metal-catalyzed C-H functionalization is one of the effective strategies to construct carbon-carbon bonds and carbon hybrid key,It avoids the disadvantages of the traditional transition-metal-catalyzed coupling reaction,such as the requirement of prefunctionzaliz-ation substrates,low atom economy,the lengthy steps and the large number of by-products of reaction.It is one of the important contents of modern organic synthesis research.And the directing group are introduced in the substrates caused wide attention,because it can further improve the regioselectivity of reaction,provide effective synthetic strategy for a series of active natural products and complex organic compounds.Directing group activation strategy based on different elements has been used in the synthesis of organic molecules in recent years.Sulfoximide is a kind of heteroatomic compound with stable three-dimensional configuration and easy to obtain.It is an important structural scaffold in many natural products and important medicinal compounds,and has a variety of uses in asymmetric synthesis,crop protection and pharmaceutical chemistry.Its cyclosulfonimide,also known as benzothiazide,is a non-aromatic heterocyclic compound containing sulfuric nitrogen and a stereocentric center.It is an important organic scaffold material for synthesis and has been found in many molecules with medicinal value and has a broad application prospect.If sulfoximide is used as the directing group and the transition metal is used to catalyze the activation of the orthotopic C-H bond of sulfoximide,and then the functional group reaction occurs,a series of molecules with physiological activity and medicinal value can be obtained.Based on this,this paper mainly carries out the following two aspects of work:(1)Precursor to NH sulfoxide imide and benzene acetylene as basic raw materials,transition metal palladium as catalyst,CuO as oxidant,1-Adm-CO2H and CsOAc as additive respectively,Dioxane as solvent,in the presence of CsF,by C-H/N-H key activation cyclization reaction,synthesis of a series of diphenyl and thiazine derivatives.Through aromatic alkyne,a thick ring is introduced directly into the molecule of benzothiazine.This is the first time that the C-H bond activation strategy has been applied to the construction of dibenzothiazide skeleton.The method is simple and easy to get raw materials and mild reaction conditions,which realizes the construction of C-C and C-N bonds,and shortens the synthesis route,which conforms to the concept of green environmental protection.(2)With NH sulfoximide as the guiding group,the sulfoximide and maleimide[4+1]cyclization product benzothiazoles were prepared under rhodium catalysis.successful to introduce the molecules can be derived for a variety of skeleton succinyl imine structure to benzothiazoles,one step to build the good screw ring rigidity,simple accessible raw materials,good compatibility of functional groups,and reaction with high regioselectivity.