title: CeCl3·7H2O catalyzed C-C and C-N bond-forming cascade cyclization with subsequent side-chain functionalization and rearrangement: a domino approach to pentasubstituted pyrrole analogues.
abstract: CeCl(3)·7H(2)O is found as an efficient catalyst for new intermolecular domino reactions of three-, four- and seven-component assemblies of common precursors under benign reaction conditions. Generation of enaminioesters from β-keto esters and primary amines, activation of their allylic sp(3) C-H, vinylic sp(2) C-H and N-H bonds, multi C-C and C-N bond-forming cascade cyclization with 1,2-diketones and subsequent side-chain alkylation have been developed to construct functionalized pentasubstituted pyrroles and their chiral analogues. The scope of the domino reaction is successfully explored toward synthesis of highly aryl-substituted pyrroles, pentasubstituted pyrroles bearing C2-olefinic side-chain and spiro-2-pyrrolinones and their chiral analogues via unusual side-chain amination, elimination and ring contraction. The new domino reaction is operationally simple, robust, substrate specific, selective and high yielding.
authors.affiliation: Department of Chemistry, University of Calcutta, University College of Science, 92, A. P. C. Road, Kolkata-700009, India.
authors.forename: Dipankar
authors.initials: D
authors.lastname: Dhara
authors.forename: Krishnanka S
authors.initials: KS
authors.lastname: Gayen
authors.forename: Saikat
authors.initials: S
authors.lastname: Khamarui
authors.forename: Palash
authors.initials: P
authors.lastname: Pandit
authors.forename: Sukla
authors.initials: S
authors.lastname: Ghosh
authors.forename: Dilip K
authors.initials: DK
authors.lastname: Maiti
mesh_terms: D002384:Catalysis; D002563:Cerium / Q000737:chemistry*; D003500:Cyclization; D015394:Molecular Structure; D011758:Pyrroles / Q000138:chemical synthesis* / Q000737:chemistry*
chemical_list: D011758:Pyrroles; D002563:Cerium; C026690:cerous chloride