Alkene Functionalization Based On Photoredox And Transition-metal Catalysis

Functionalization of alkenes,abundant and readily available chemical feedstocks,is a fundamental transformation in organic synthetic chemistry which provides structurally diverse molecules through fast and simple construction of new bonds.Thus it has been a hot topic in chemical research for many years.In this context,development of mild,environment friendly and energy efficient processes for alkenes functionalization reactions with sustainable,naturally abundant and environmentally benign transition-metal catalysts is highly desirable considering the increasingly serious environmental pollution and energy crisis.Therefore,the research contents of this doctoral dissertation focus on the study of alkene functionalization in a green manner.In this thesis,our advance in alkenes functionalization through visible-light promotion,copper and manganese catalysis will be covered.Two chapters containing four sections to introduce detailed description are as follows:1.We have developed a novel method for the synthesis of densely functionalized pyrroline derivatives via visible-light promoted carboimination of unactivated alkenes by selective formation of C-N/C-C bond within one step.This reaction is simple to operate,mild conditions and broad substrate scopes.The practicality of this transformation has been demonstrated by gram scale reaction which produced the core framework of pyrrolines in 65%yield with medium selectivity.2.Based on this strategy,we also developed a divergent methodology for the synthesis of hydro/oxyimination products through the intramolecular 5-exocy-clization of an iminyl radical,which is generated by virtue of visible-light-promoted mesolysis of O-acyl oxime derivatives.This protocol provides an efficient access to 3,4-pyrroline derivatives via C-N bond formation.A wide range of substrates can be accommodated in this reaction and yield the desired products in good to excellent yields.3.Then a copper catalyzed the cyclization of N-4-alkenyl-N-pivalicoxysulfon-amide derivatives was developed for the synthesis of corresponding cis-2,5-disubstituted pyrrolidines.The cis-configuration products could be further manipulated for the synthesis of drug molecules or nature products which contained the core framework of cis-2,5-disubstituted pyrrolidines.4.Finally,the manganese-catalyzed arylation of gem-difluoroalkene via C-H activation and C-F cleavage was achieved.In contrast to previously reported methods which always only afford the Z-selectivity product or as the major product,this present method could provide a very useful and rare E isomer as the major product.This strategy not only represents an important progress in manganese catalysis,but also offers an alternative way for the synthesis of fluoroalkenes.