Rhodium(III)-Catalyzed Sequential Cyclization of <i>N</i>-Boc Hydrazones with Propargylic Monofluoroalkynes via C–H Activation/C–F Cleavage for the Synthesis of Spiro[cyclobutane-1,9′-indeno[1,2-<i>a</i>]indenes]
Cheng Deng, Jiang Lu, Jinzhong Yao, Qian Liang, Lin Miao, Changchang Li, Maozhong Miao, Hongwei Zhou
Abstract
An effective rhodium(III) catalysis for the construction of valuable tetracyclic compounds is described herein. This domino process involving the C–H activation/[3 + 2] annulation/intramolecular Friedel–Crafts reaction sequences of simple and readily available N-Boc hydrazones and propargylic monofluoroalkynes afforded fused tetracyclic spiro[cyclobutane-1,9′-indeno[1,2-a]indenes] in moderate to good yields, featuring three C–C bond formation. Moreover, control experiments indicated that the C–H activation might be involved in the rate-determining step.
Topics & Concepts
CyclobutaneChemistryRhodiumIntramolecular forceAnnulationCatalysisDominoStereochemistryCleavage (geology)Bond cleavageMedicinal chemistryCombinatorial chemistryRing (chemistry)Organic chemistryEngineeringFracture (geology)Geotechnical engineeringCatalytic C–H Functionalization MethodsCatalytic Alkyne ReactionsSulfur-Based Synthesis Techniques