title: Cobalt(II) Porphyrin-Catalyzed Intramolecular Cyclopropanation of N-Alkyl Indoles/Pyrroles with Alkylcarbene: Efficient Synthesis of Polycyclic N-Heterocycles.
abstract: A protocol on chemoselective cobalt(II) porphyrin-catalyzed intramolecular cyclopropanation of N-alkyl indoles/pyrroles with alkylcarbenes has been developed. The reaction enables the rapid construction of a range of nitrogen-containing polycyclic compounds in moderate to high yields from readily accessible materials. These N-containing polycyclic compounds can be converted into a variety of N-heterocycles with potential synthetic and biological interest. Compared to their N-tosylhydrazone counterparts, the use of bulky N-2,4,6-triisopropylbenzenesulfonyl hydrazones as carbene precursors allows cyclopropanation to occur under milder reaction conditions.
authors.affiliation: HKU Shenzhen Institute of Research & Innovation, Shenzhen, China.|State Key Laboratory of Synthetic Chemistry and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, China.
authors.forename: Annapureddy Rajasekar
authors.initials: AR
authors.lastname: Reddy
authors.affiliation: HKU Shenzhen Institute of Research & Innovation, Shenzhen, China.|State Key Laboratory of Synthetic Chemistry and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, China.
authors.forename: Fei
authors.initials: F
authors.lastname: Hao
authors.affiliation: HKU Shenzhen Institute of Research & Innovation, Shenzhen, China.|State Key Laboratory of Synthetic Chemistry and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, China.
authors.forename: Kai
authors.initials: K
authors.lastname: Wu
authors.affiliation: HKU Shenzhen Institute of Research & Innovation, Shenzhen, China. cyzhou@hku.hk.|State Key Laboratory of Synthetic Chemistry and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, China. cyzhou@hku.hk.
authors.forename: Cong-Ying
authors.initials: CY
authors.lastname: Zhou
authors.affiliation: HKU Shenzhen Institute of Research & Innovation, Shenzhen, China. cmche@hku.hk.|State Key Laboratory of Synthetic Chemistry and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, China. cmche@hku.hk.
authors.forename: Chi-Ming
authors.initials: CM
authors.lastname: Che
keywords: carbenes; cobalt; fused-ring systems; heterocycles; porphyrinoids