Copyright © 2014 The Chemical Society of Japan and Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Volume 11, Issue 5
Article first published online: 29 SEP 2011 | DOI: 10.1002/tcr.201190017
The medal in the round-bottom flask on the left side contains a graphic from within this issue. If you can find where this graphic is contained, send an email to ChemicalRecord@wiley-vch.de with the page number; the first correct respondent receives a free book from Wiley-VCH!
Article first published online: 29 SEP 2011 | DOI: 10.1002/tcr.201190018
Article first published online: 6 SEP 2011 | DOI: 10.1002/tcr.201100022
Endeavors in the functionalization of fullerenes have led to the development of new reactions, several of which are highlighted in this account: organoboron addition to fullerenes, CH bond allylation and arylation of organo(hydro)fullerenes, CH/CC bond cleavage of alkynyl(hydro)fullerenes, regioselective tetraallylation of fullerenes, double nucleophilic substitution of aziridinofullerene, and [2 + 2] cycloaddition of aziridinofullerene with alkynes. These works not only demonstrate the potential of molecular catalysis for fullerene functionalization, but also unlock opportunities for markedly different strategies in nanocarbon synthesis.
Shogo Hashizume, Kounosuke Oisaki and Motomu Kanai
Article first published online: 6 SEP 2011 | DOI: 10.1002/tcr.201100024
Outer-sphere redox catalysis is key to efficient C-H activation. As one example, a CuI-catalyzed oxidative coupling between nitrones and various ethers or amines is described. Predictable site-selective C-C bond formation was achieved through activation of the C-H bonds in each coupling partner and the migration of a C-N double bond. Mechanistic studies strongly suggested that the reaction proceeded via an oxonium/iminium cation species as the key intermediate and pave the way for future extension of outer-sphere redox catalysis.
Article first published online: 6 SEP 2011 | DOI: 10.1002/tcr.201100023
Nickel catalysts effect the hydroarylation of alkynes through functionalization of C–H bonds of arenes including benzo-fused five-membered heteroarenes, pyridine-N-oxides, pyridines, 2-pyridones, and perfluoroarenes. The reactions proceed with excellent stereo- and regioselectivity to give disubstituted arylethenes in good yields. The use of Lewis acid (LA) co-catalysts is crucial for the reaction of imidazoles, pyridines, and 2-pyridones.
Article first published online: 6 SEP 2011 | DOI: 10.1002/tcr.201100026
Controlled formation of oligomeric flavans has become possible by an orthogonal synthetic methodology. Bromo-capping of the C(8)-position of the flavan skeleton enabled the equimolar coupling of electrophilic and nucleophilic flavan oligomers. The block synthesis was efficiently performed for the assembly of higher oligomeric structures.
Shigeki Matsunaga and Tatsuhiko Yoshino
Article first published online: 6 SEP 2011 | DOI: 10.1002/tcr.201100020
Catalytic asymmetric synthesis of unnatural amino acids with vicinal tetrasubstituted chiral carbon stereocenters is described. Direct catalytic asymmetric aldol reaction of simple non-activated ketone electrophiles with α-substituted α-isothiocyanato ester donors was realized, whereby a Mg/Schiff base catalyst promoted the aldol reaction and α-amino-β-hydroxy esters were obtained in up to 98% ee and 98:2 d.r. Further, the Mg/Schiff base catalyst and a Sr/Schiff base catalyst were utilized for stereodivergent direct asymmetric Mannich-type reaction of ketimines, providing syn-α,β-diamino esters and anti-α,β-diamino esters in good to high enantioselectivity, respectively.
Article first published online: 7 SEP 2011 | DOI: 10.1002/tcr.201100009
Insulated π-conjugated molecules, in which the π-conjugated compounds are covered by a cyclic protective sheath, have attracted considerable attention because of their potential applicability in next-generation mono-molecular electronic devices. New methods are presented for synthesizing insulated π-conjugated molecules involving the self-inclusion of rotaxane precursors linking π-conjugated units as a guest and permethylated cyclodextrin as a macrocyclic host, and a new method for synthesizing insulated molecular wires through the polymerization of insulated π-conjugated molecules as monomers is highlighted. In this account, the synthetic methodologies and characteristic of insulated π-conjugated molecules and insulated molecular wires are discussed.
Article first published online: 8 SEP 2011 | DOI: 10.1002/tcr.201100014
Antillatoxin and polytheonamide B are cytotoxic non-ribosomal peptides, both isolated from marine sources, that possess unique biological activities relating to ion channel proteins. The goal of this research program is to control the function and behavior of ion channels in a desired fashion by exploiting structural motifs of these natural products. In the opening phase of this program, we first developed general and efficient synthetic routes to antillatoxin and polytheonamide B. The strategies for the total syntheses were then applied to the preparation of structurally varied derivatives for studies of structure-function relationships, which resulted in deciphering important structural elements for the potent biological activities of these natural products.
Article first published online: 29 SEP 2011 | DOI: 10.1002/tcr.201190019
Article first published online: 29 SEP 2011 | DOI: 10.1002/tcr.201190020