title: Unprecedented Double aza-Michael Addition within a Sapphyrin Core.
abstract: A novel sapphyrin derivative was obtained from the reaction between a free-base sapphyrin and dimethyl acetylenedicarboxylate (DMAD). The formation of the new compound involved a double aza-Michael addition of two pyrrolic NH groups to a DMAD molecule, with the formation of a disubstituted ethano bridge. The NMR spectral data reveal a product with an unsymmetrical structure; DFT calculations provided support for a structure in which the ethano bridge links two adjacent pyrrole units. The present study provides a seemingly unprecedented example of an N,N'-dinucleophile reacting with DMAD to form a heterocyclic compound in which the two N-atoms are linked to the two sp(3) carbon atoms derived from a substituted acetylene.
authors.affiliation: Department of Chemistry & QOPNA, University of Aveiro, 3810-193, Aveiro, Portugal.
authors.forename: Flávio
authors.initials: F
authors.lastname: Figueira
authors.affiliation: Department of Chemistry & CICECO, University of Aveiro, 3810-193, Aveiro, Portugal.|Department of Medical Sciences & iBiMED, University of Aveiro, 3810-193, Aveiro, Portugal.
authors.forename: Igor
authors.identifier: http://orcid.org/0000-0003-4971-9932
authors.initials: I
authors.lastname: Marques
authors.affiliation: Department of Chemistry & QOPNA, University of Aveiro, 3810-193, Aveiro, Portugal.
authors.forename: Andreia S F
authors.initials: AS
authors.lastname: Farinha
authors.affiliation: Department of Chemistry & QOPNA, University of Aveiro, 3810-193, Aveiro, Portugal.
authors.forename: Augusto C
authors.initials: AC
authors.lastname: Tomé
authors.affiliation: Department of Chemistry & QOPNA, University of Aveiro, 3810-193, Aveiro, Portugal.
authors.forename: José A S
authors.initials: JA
authors.lastname: Cavaleiro
authors.affiliation: Department of Chemistry & QOPNA, University of Aveiro, 3810-193, Aveiro, Portugal.
authors.forename: Artur M S
authors.initials: AM
authors.lastname: Silva
authors.affiliation: Department of Chemistry, The University of Texas at Austin, 105 E. 24th Street-A5300, Austin, TX, 78712-1224, USA.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Sessler
authors.affiliation: Department of Chemistry & CICECO, University of Aveiro, 3810-193, Aveiro, Portugal. vitor.felix@ua.pt.|Department of Medical Sciences & iBiMED, University of Aveiro, 3810-193, Aveiro, Portugal. vitor.felix@ua.pt.
authors.forename: Vítor
authors.identifier: http://orcid.org/0000-0001-9380-0418
authors.initials: V
authors.lastname: Félix
authors.affiliation: Department of Chemistry & QOPNA, University of Aveiro, 3810-193, Aveiro, Portugal. jtome@tecnico.ulisboa.pt.|Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001, Lisboa, Portugal. jtome@tecnico.ulisboa.pt.
authors.forename: João P C
authors.identifier: http://orcid.org/0000-0001-6057-4936
authors.initials: JP
authors.lastname: Tomé
mesh_terms: D000114:Acetylene / Q000138:chemical synthesis / Q000737:chemistry; D000480:Alkynes / Q000138:chemical synthesis / Q000737:chemistry*; D061565:Cycloaddition Reaction / Q000379:methods*; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D011166:Porphyrins / Q000138:chemical synthesis / Q000737:chemistry*; D011758:Pyrroles / Q000138:chemical synthesis / Q000737:chemistry
chemical_list: D000480:Alkynes; D011166:Porphyrins; D011758:Pyrroles; C440448:sapphyrin; C022918:acetylenedicarboxylic acid dimethyl ester; D000114:Acetylene
keywords: Michael addition; anions; cycloaddition; density functional calculations; porphyrinoids