title: Exploiting the Distal Reactivity of Indolyl Methylenemalononitriles: An Asymmetric Organocatalyzed [4+2] Cycloaddition with Enals Enables the Assembly of Elusive Dihydrocarbazoles.
abstract: An unprecedented technique for the in situ generation of indolyl ortho-quinodimethanes from 2-methylindole-based methylenemalononitriles by amine-mediated remote C(sp(3) )-H deprotonation was developed. These intermediates were efficiently trapped by diverse enals to provide a rapid entry to 2,9-dihydro-1H-carbazole-3-carboxyaldehyde structures through a formal asymmetric [4+2] eliminative cycloaddition governed by a α,α-diphenylprolinol trimethylsilyl ether catalyst.
authors.affiliation: Istituto di Chimica Biomolecolare, Consiglio Nazionale delle Ricerche, Traversa La Crucca 3, 07100, Li Punti Sassari, Italy. gloria.rassu@icb.cnr.it.
authors.forename: Gloria
authors.identifier: http://orcid.org/0000-0001-8241-2022
authors.initials: G
authors.lastname: Rassu
authors.affiliation: Dipartimento di Farmacia, Università degli Studi di Parma, Parco Area delle Scienze 27A, 43124, Parma, Italy. claudio.curti@unipr.it.
authors.forename: Claudio
authors.identifier: http://orcid.org/0000-0002-6117-1503
authors.initials: C
authors.lastname: Curti
authors.affiliation: Istituto di Chimica Biomolecolare, Consiglio Nazionale delle Ricerche, Traversa La Crucca 3, 07100, Li Punti Sassari, Italy.
authors.forename: Vincenzo
authors.identifier: http://orcid.org/0000-0001-7527-4645
authors.initials: V
authors.lastname: Zambrano
authors.affiliation: Dipartimento di Chimica e Farmacia, Università degli Studi di Sassari, Sassari, Italy.
authors.forename: Luigi
authors.identifier: http://orcid.org/0000-0002-5223-2255
authors.initials: L
authors.lastname: Pinna
authors.affiliation: Dipartimento di Farmacia, Università degli Studi di Parma, Parco Area delle Scienze 27A, 43124, Parma, Italy.|Dipartimento di Scienze degli Alimenti, Università degli Studi di Parma, Parma, Italy.
authors.forename: Nicoletta
authors.identifier: http://orcid.org/0000-0002-7928-4207
authors.initials: N
authors.lastname: Brindani
authors.affiliation: Dipartimento di Chimica, Università degli Studi di Parma, Parma, Italy.
authors.forename: Giorgio
authors.identifier: http://orcid.org/0000-0002-7946-0602
authors.initials: G
authors.lastname: Pelosi
authors.affiliation: Dipartimento di Farmacia, Università degli Studi di Parma, Parco Area delle Scienze 27A, 43124, Parma, Italy.
authors.forename: Franca
authors.identifier: http://orcid.org/0000-0001-7451-781X
authors.initials: F
authors.lastname: Zanardi
keywords: asymmetric synthesis; cycloaddition; heterocycles; organocatalysis; vinylogy