Rh(III)-Catalyzed Spiroannulation Reaction of <i>N</i>-Aryl Nitrones with 2-Diazo-1,3-indandiones: Synthesis of Spirocyclic Indole-<i>N</i>-oxides and Their 1,3-Dipolar Cycloaddition with Maleimides
Shenghai Guo, Ziyi Zhang, Zhaotong Wei, Yuanqing Zhu, Xuesen Fan
Abstract
An efficient strategy for the preparation of spirocyclic indole- N -oxide compounds through a Rh(III)-catalyzed [4 + 1] spiroannulation reaction of N -aryl nitrones with 2-diazo-1,3-indandiones as C1 synthons under extremely mild conditions is presented. From this reaction, 40 spirocyclic indole- N -oxides were easily obtained in up to 98% yield. In addition, the title compounds could be successfully used for the construction of structurally intriguing maleimide-containing fused polycyclic scaffolds via a diastereoselective 1,3-dipolar cycloaddition reaction with maleimides.
Topics & Concepts
DiazoSynthonCycloadditionChemistryIndole testMaleimideArylCatalysis1,3-Dipolar cycloadditionYield (engineering)Medicinal chemistryOrganic chemistryCombinatorial chemistryMaterials scienceMetallurgyAlkylCyclopropane Reaction MechanismsCatalytic C–H Functionalization MethodsSynthesis and Catalytic Reactions