[4+1] Spirocyclization Reaction Catalyzed By Trivalent Rhodium

Spiro compounds as a class of molecules with three-dimensional structures are widely used in natural products,biologically active substances and functional materials.Transition metal-catalyzed C-H bond activation has been established as an efficient strategy for synthesis of cyclic（spiro）molecules due to its high atom economy and step economy.In these reports,rhodium（Ⅲ）catalysis has been extensively studied due to their advantages such as high activity and high selectivity.Especially Rh（Ⅲ）-catalyzed[4+1]annulation reaction,various fivemembered ring compounds has been prepared by using a variety of different types of coupling components as C1 synthons.However,due to the unique rigid structure of the spirocyclic scaffolds,the Rh（Ⅲ）-catalyzed synthesis strategy is mainly based on the[3+2]type,and there are only few reports on the[4+1]type of reaction.Therefore,it is necessary to search and design suitable C1 synthons to realize the diverse construction of spirocycles by Rh（Ⅲ）-catalyzed[4+1]annulation.This thesis mainly focused on Rh（Ⅲ）-catalyzed[4+1]spirocyclic reaction.The cyclic 1diazonaphthelen-2（1H）-one was designed as Cl synthon and reacted with suitable arenes to realize the construction of spirocyclic compounds.The results are as following:1)Cp*Rh（Ⅲ）-catalyzed oxidative[4+1]spiroannulation has been realized via C-H activation of oximes and benzoic acids with 1-diazonaphthelen-2（1H）-ones.This annulation system proceeded with high functional group compatibility under mild conditions,and provides a directly strategy for the synthesis of spirocyclic isoindole N-oxides and isobenzofuranones.2)The enantioselectivity[4+1]spirocyclic reactions of oxime,2-methoxybenzoic acid,ketene dithioacetal,and N-phenylnitrone with 1-diazonaphthalene-2（1H）-ones were achieved under chiral CpXRh（Ⅲ）.And the products of N-phenylnitrone have great chiral synthesis potential.