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Rational Synthesis of Antiaromatic 5,15‐Dioxaporphyrin and Oxidation into β,β‐Linked Dimers
Author(s) -
Nishiyama Akihide,
Fukuda Masaya,
Mori Shigeki,
Furukawa Ko,
Fliegl Heike,
Furuta Hiroyuki,
Shimizu Soji
Publication year - 2018
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201804648
Subject(s) - antiaromaticity , intramolecular force , aromaticity , lone pair , chemistry , ring (chemistry) , reactivity (psychology) , annulation , porphyrin , molecule , nucleophile , photochemistry , computational chemistry , stereochemistry , organic chemistry , catalysis , medicine , alternative medicine , pathology
5,15‐Dioxaporphyrin was synthesized for the first time by a nucleophilic aromatic substitution reaction of a nickel bis(α,α′‐dibromodipyrrin) complex with benzaldoxime, followed by an intramolecular annulation of the α‐hydroxy‐substituted intermediate. This unprecedented molecule is a 20π‐electron antiaromatic system, in terms of Hückel's rule of aromaticity, because lone pair electrons of oxygen atoms are incorporated into the 18π‐electron conjugated system of the porphyrin. A theoretical analysis based on the gauge‐including magnetically induced current method confirmed its antiaromaticity and a dominant inner ring pathway for the ring current. The unique reactivity of 5,15‐dioxaporphyrin forming a β,β‐linked dimer upon oxidation was also revealed.