Hiroshi Shinokubo

Abstract Organomagnesium compounds are among the most useful organometallic reagents in organic synthesis. Besides their classical nucleophilic reactions to carbonyl compounds, Grignard reagents gain versatile reactivity when combined with various transition metal salts. In this article, we review mainly our own studies on manganese‐, iron‐, chromium‐, and cobalt‐catalyzed carbon−carbon bond formation reactions using Grignard reagents. Other closely related research in this field is also discuss

Which way to go: The product distribution in the efficient oxidation of 2-aminoanthracene derivatives to pyrazine- and pyrrole-fused bisanthracenes can be controlled by additives (see scheme; TFA=trifluoroacetic acid, DDQ=2,3-dichloro-5,6-dicyano-1,4-benzoquinone). The pyrrole-fused dimer can be regarded as an aza[7]helicene with a stable helical conformation. Detailed facts of importance to specialist readers are published as ”Supporting Information”. Such documents are peer-reviewed, but not c

The development of porphyrin synthesis by means of transition metal-catalyzed reactions is explored in this feature article. Porphyrins have been receiving much attention in a wide area of chemistry as functional dyes, non-linear optical materials, ligands for a variety of metals, structural motifs in supramolecules, and so forth. However, they have been merely recognized as a reaction substrate in transition metal-catalyzed transformations. Recently, application of such new methodologies to por

We designed and synthesized molecular tweezers consisting of nitrogen-embedded buckybowl subunits. The judicious choice of the covalent linkers modulated their binding strength with C₆₀ or C₇₀ in solution. Titration studies by optical and ¹H NMR analyses revealed a 1:1 composition of the resulting complexes. X-ray diffraction analysis elucidated their solid-state structures, in which two azabuckybowl units surround one fullerene molecule. The large association co

Directly linked corrole dimer <b>1</b>, which has a planar cyclooctatetraene in its core, has been synthesized from 2-borylcorrole in excellent yield. 2,3-Dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) oxidation of <b>1</b> provides its oxidized form <b>4</b>, which has two NH protons in each corrole core. Dicorrole <b>4</b> and its Zn(II) complex <b>6</b> exhibit broad electronic absorption spectra, and magnetic measurement has revealed t

The reversible formation of σ-bonds between organic radicals has been widely investigated. However, reports on the formation of σ-dimers from delocalized π-radical cations are scarce. Herein, we report the reversible σ-dimerization behavior of a bowl-shaped π-radical cation generated from a nitrogen-embedded buckybowl, both in the crystalline state and in solution. The detailed structure of the σ-dimer in the crystalline state was determined by a single-crystal X-ray diffraction analysis. The mo

Klein ist wunderschön: Das ringverengte Porphyrin-Derivat Norcorrol wurde effizient an einem Nickel-Templat synthetisiert. Der resultierende Norcorrol-Komplex ist zwar nach der Hückel-Regel deutlich antiaromatisch, erwies sich aber als stabil und konnte durch Oxidation in einen aromatischen Oxacorrol-Komplex überführt werden. Detailed facts of importance to specialist readers are published as ”Supporting Information”. Such documents are peer-reviewed, but not copy-edited or typeset. They are mad

Synthesis of nickel(II) complexes of meso-aryl-substituted azacorroles was performed by Buchwald-Hartwig amination of a dipyrrin Ni(II) complex with benzylamine through C-N and C-C coupling. The highly planar structure of Ni(II) azacorroles was elucidated by X-ray diffraction analysis. (1)H NMR analysis and nucleus independent chemical shift (NICS) calculation on Ni(II) azacorrole revealed its distinct aromaticity with [17]triaza-annulene 18π conjugation. In addition, acylation of azacorrole sel