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Covalent organic cages have potential applications in molecular inclusion/recognition and porous organic crystals. Bridging arene units with sp3 atoms enables facile construction of rigid isolated internal vacancies, and various prismatic arene cages have been synthesized by kinetically controlled covalent bond formation. However, the synthesis of a tetrahedral one, which requires twice as much bond formation as prismatic ones, has been limited to a thermodynamically controlled dynamic SNAr reaction, and this reversible covalent bond formation made the resulting cage product chemically unstable. Here we report the Rh‐catalyzed high‐yielding and highly 1,3,5‐selective room temperature [2+2+2] cycloaddition of push‐pull alkynes and its application to the synthesis of chemically stable aryl ether cages of various shapes and sizes, including prismatic and tetrahedral forms. These aryl ether cages are highly crystalline and intertwine with each other to form regular packing structures. Some aryl ether cages encapsulated isolated water molecules in their hydrophobic cavity by hydrogen bonding with the multiple ester moieties. [ABSTRACT FROM AUTHOR]

A high‐yielding new route to substituted cycloparaphenylenes has been developed via reductive aromatization of a diyne bearing two cyclohexadiene units giving a cyclophenylene‐ethynylene (CPE) followed by the cationic rhodium(I)/dppe complex‐catalyzed intermolecular [2+2+2] cycloaddition (cycloaromatization) of the CPE with monoynes. The thus‐obtained products, substituted [8]cycloparaphenylene‐triphenylenes ([8]CPPTs), exhibited definite aggregation‐induced emission (AIE). This molecule is noteworthy as a novel AIE‐active cycloarylene that does not have well‐known AIE luminogens, such as tetraphenylethene and 1,2,4,5‐tetraphenylbenzene skeletons. The single‐crystal X‐ray diffraction analyses of the AIE‐active [8]CPPTs revealed their highly ordered packing structures in which the rotation of the triphenylene moieties is restricted. [ABSTRACT FROM AUTHOR]

We report the synthesis of a [20]cyclophenacene‐type cyclophenylene‐naphthylene (CPN) belt and the enantioselective synthesis of chiral‐type CPN belts (up to >99 % ee) by the cationic rhodium(I)‐catalyzed intramolecular [2+2+2] cycloaddition of naphthalene‐embedded cyclic polyynes. The synthesis of a depth‐expanded CPN belt was also attempted, but the final intramolecular [2+2+2] cycloaddition was unsuccessful. Theoretical calculations clarified that the reactivity depends on the stability of the transition state in the initial oxidative cycloaddition step which is subject to molecular strain. The cylindrical structures of these CPN belts were confirmed by X‐ray crystallographic analyses. As a result of π‐extension through the introduction of naphthalenes in the chiral‐type CPN belts, the anisotropy dissymmetry factors of electronic circular dichroism and circularly polarized luminescence are amplified compared with the corresponding zigzag‐type chiral cyclophenylene belts. [ABSTRACT FROM AUTHOR]

The synthesis of alternating donor-acceptor [12] and [16]cycloparaphenylenes (CPPs) has been achieved by the rhodium-catalyzed intermolecular cross-cyclotrimerization followed by imidation and/or aromatization. These alternating donor-acceptor CPPs showed positive solvatofluorochromic properties and smaller HOMO-LUMO gaps compared with nonfunctionalized CPPs, which was confirmed by the theoretical study. [ABSTRACT FROM AUTHOR]

It has been established that cationic rhodium(I)/axially chiral biaryl bis(phosphine) complexes catalyze the asymmetric [2+2+2] cycloaddition of 1,6-enynes with electron-rich functionalized alkenes, enamides, and vinyl carboxylates, to produce the corresponding protected cyclohexenylamines and cyclohexenols. Interestingly, regioselectivity depends on structures of substrates. The present cycloaddition was successfully applied to the enantioselective total synthesis of (−)-porosadienone by using the amide moiety as a leaving group. [ABSTRACT FROM AUTHOR]

It has been established that an electron-deficient CpE rhodium(III) complex catalyzes the oxidative [4+2] annulation of substituted arenecarboxylic and acrylic acids with alkynes under ambient conditions (at RT-40 °C, under air) without using excess amounts of substrates to produce the corresponding substituted isocoumarins and α-pyrones in high yields. Minor modification of reaction conditions depending on the coordination ability of alkynes realized the high efficiency. [ABSTRACT FROM AUTHOR]

An electron-deficient CpE rhodium(III) complex bearing a cyclopentadienyl ligand with two ethyl ester substituents catalyzes the tandem [2+2+2] annulation-lactamization of acetanilides with two alkynoates via cleavage of adjacent two C−H bonds to give densely substituted benzo[ cd]indolones. The reactions of meta-methoxy-substituted acetanilides with two alkynoates also provided benzo[ cd]indolones via cleavage of adjacent C−H/C−O bonds. Furthermore, 3,5-dimethoxyacetanilides reacted with two alkynoates to give dearomatized spiro compounds. [ABSTRACT FROM AUTHOR]

Keywords: Cyclophenylene-Naphthylene Belts; DFT Calculations; Planar Chirality; Rhodium; [2+2+2] Cycloaddition EN Cyclophenylene-Naphthylene Belts DFT Calculations Planar Chirality Rhodium [2+2+2] Cycloaddition 1 1 1 03/30/22 20220404 NES 220404 B A naphthalene-embedded b conjugated nanobelt is an excellent design for achieving the synthesis of cyclophenacene-type and chiral-type carbon nanobelts. A cationic rhodium complex catalyst is a powerful tool for the (asymmetric) synthesis of these analogues, as reported by Ken Tanaka and co-workers in their Research Article (e202200800). Inside Back Cover: Synthesis of Cyclophenacene- and Chiral-Type Cyclophenylene-Naphthylene Belts (Angew. [Extracted from the article]

In der Abbildung stellen die drei blauen Bänder im Vordergrund und der Rhodiumkomplex im Hintergrund die Cyclophenylen-Naphthylen-Bänder bzw. den Katalysator dar. Cyclophenylene-Naphthylene Belts, DFT Calculations, Planar Chirality, Rhodium, [2+2+2] Cycloaddition Keywords: Cyclophenylene-Naphthylene Belts; DFT Calculations; Planar Chirality; Rhodium; [2+2+2] Cycloaddition EN Cyclophenylene-Naphthylene Belts DFT Calculations Planar Chirality Rhodium [2+2+2] Cycloaddition 1 1 1 03/30/22 20220404 NES 220404 B Ein konjugierter Nanogürtel b ist ein hervorragendes Design für die Synthese von Kohlenstoff-Nanobelts des Cyclophenacen-Typs und des chiralen Typs. [Extracted from the article]

An electron ‐ deficient CpE ‐ rhodium(III) complex catalyzes the tandem [2+2+2] annulation–lactamization of acetanilides with two alkynoates via cleavage of two adjacent C−H bonds to give densely substituted benzo[cd]indolones. Surprisingly, the reactions of meta ‐ methoxy ‐ substituted acetanilides with two alkynoates also provided benzo[cd]indolones via unprecedented cleavage of adjacent C−H and C−O bonds. In contrast, 3,5 ‐ dimethoxyacetanilides reacted with two alkynoates to give dearomatized spiro compounds. More information can be found in the Communication by Yu Shibata, Ken Tanaka et al. on page   2260 in Issue 16, 2016 (DOI: 10.1002/asia.201600943). [ABSTRACT FROM AUTHOR]

Cycloparaphenylene Organic molecules with a cyclic π‐conjugation, such as cycloparaphenylene (CPP), have attracted much attention because of their fascinating structures, unique properties, and potential applications in materials science. In their Communication on page 18900 ff., K. Tanaka and co‐workers report the concise synthesis of C3‐symmetrical [12]CPP‐hexacarboxylate by a rhodium‐catalyzed macrocyclization. Further, a structurally uniform nanotube assembly was achieved in the crystalline state through multiple hydrogen‐bonding interactions between C3‐symmetrical functionalization of CPP and highly polar alkoxycarbonyl groups. [ABSTRACT FROM AUTHOR]