title: Preparation of azulene-derived fulvenedialdehydes and their application to the synthesis of stable adj-dicarbaporphyrinoids.
abstract: A "2 + 2" strategy for synthesizing adj-dicarbaporphyrinoid systems has been developed. In a model study, an azulenylmethylpyrrole dialdehyde was condensed with a dipyrrylmethane in the presence of HCl, followed by oxidation with ferric chloride, to give a modest yield of an azuliporphyrin. Fulvene aldehydes were prepared by reacting an indene-derived enamine with azulene aldehydes in the presence of Bu(2)BOTf, and azulene dialdehydes similarly reacted to give fulvene dialdehydes. The dialdehydes were condensed with dipyrrylmethanes in TFA/dichloromethane to afford good to excellent yields of dicarbaporphyrinoids with adjacent indene and azulene subunits. These 22-carbaazuliporphyrins exhibited significant diatropic character, and this property was magnified upon protonation. These characteristics are attributed to tropylium-containing resonance contributors that possess 18π electron delocalization pathways. Protonation studies demonstrated that C-protonation readily occurred at the interior indene carbon, but deuterium exchange also occurred at the internal azulene CH as well as at the meso-positions with TFA-d. Reaction of a carbaazuliporphyrin with silver(I) acetate in methanol or ethanol solutions also gave unusual nonaromatic dialkoxy derivatives.
authors.affiliation: Department of Chemistry, Illinois State University, Normal, Illinois 61790-4160, USA. tdlash@ilstu.edu
authors.forename: Timothy D
authors.initials: TD
authors.lastname: Lash
authors.forename: Aaron D
authors.initials: AD
authors.lastname: Lammer
authors.forename: Aparna S
authors.initials: AS
authors.lastname: Idate
authors.forename: Denise A
authors.initials: DA
authors.lastname: Colby
authors.forename: Kristen
authors.initials: K
authors.lastname: White
mesh_terms: D000447:Aldehydes / Q000138:chemical synthesis* / Q000737:chemistry*; D052176:Azulenes / Q000737:chemistry*; D015394:Molecular Structure; D011166:Porphyrins / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: D000447:Aldehydes; D052176:Azulenes; D011166:Porphyrins; C005525:azulene