title: Application of Nazarov type electrocyclization to access [6,5,6] and [6,5,5] core embedded new polycycles: an easy entry to tetrahydrofluorene scaffolds related to Taiwaniaquinoids and C-nor-D homosteroids.
abstract: An easy, efficient and concise approach to tetrahydrofluorene [6,5,6]ABC tricyclic core embedded new polycycles has been achieved under relatively mild and catalytic Nazarov type electrocyclization conditions, using 2 mol% of Sc(OTf)(3) in anhydrous DCM (dichloromethane) at room temperature, with high yields. The generality of the reaction has been illustrated by synthesizing diverse polycycles embedded with rare heterotricyclic [6,5,5]ABC skeletons.
authors.affiliation: Medicinal and Process Chemistry Division, Central Drug Research Institute, Lucknow, 226001, UP, India.
authors.forename: Ritesh
authors.initials: R
authors.lastname: Singh
authors.forename: Gautam
authors.initials: G
authors.lastname: Panda
mesh_terms: D002384:Catalysis; D003500:Cyclization; D004224:Diterpenes / Q000737:chemistry*; D004583:Electrons; D005449:Fluorenes / Q000138:chemical synthesis*; D006718:Homosteroids / Q000737:chemistry*; D015394:Molecular Structure
chemical_list: D004224:Diterpenes; D005449:Fluorenes; D006718:Homosteroids; C041509:fluorene