Synthesis of [8]Cycloparaphenylene-octacarboxylates via Rh-Catalyzed Stepwise Cross-Alkyne Cyclotrimerization.

The synthesis of C- and C-symmetrical [8]cycloparaphenylene (CPP)-octacarboxylates has been achieved via macrocyclization by the rhodium-catalyzed intermolecular stepwise cross-cyclotrimerization and subsequent reductive aromatization. The C-symmetrical octa-tert-butyl [8]CPP-octacarboxylate forms a dimer in which eight ester moieties face each other. The dimers are aligned so as to make a one-dimensional column with a channel structure inside.

Oxidative Annulation of Arenecarboxylic and Acrylic Acids with Alkynes under Ambient Conditions Catalyzed by an Electron-Deficient Rhodium(III) Complex.

It has been established that an electron-deficient Cp(E) 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.

Concise Synthesis and Facile Nanotube Assembly of a Symmetrically Multifunctionalized Cycloparaphenylene.

The concise synthesis of C3-symmetrical [12]CPP-hexacarboxylate has been achieved through macrocyclization by the rhodium-catalyzed intermolecular cross-cyclotrimerization and subsequent reductive aromatization. C3-Symmetrical functionalization of CPP with highly polar alkoxycarbonyl groups enabled the structurally uniform nanotube assembly in the crystalline state through multiple hydrogen-bonding interactions giving a dimer followed by one-dimensional stacking.

Enantioselective synthesis of [9]- and [11]helicene-like molecules: double intramolecular [2+2+2] cycloaddition.

The enantioselective synthesis of completely ortho-fused [9]- and [11]helicene-like molecules has been achieved through a rhodium-mediated, intramolecular, double [2+2+2] cycloaddition of phenol- or 2-naphthol-linked hexaynes. Crystal structures and photophysical properties of these [9]- and [11]helicene-like molecules have also been disclosed.

Rhodium-catalyzed one-pot intermolecular [2 + 2 + 2] trimerization/asymmetric intramolecular [4 + 2] cycloaddition of two aryl ethynyl ethers and 5-alkynals.

It has been established that a cationic Rh(I)/(R)-H(8)-BINAP complex catalyzes the one-pot intermolecular [2 + 2 + 2] trimerization/asymmetric intramolecular [4 + 2] cycloaddition of two aryl ethynyl ethers and 5-alkynals to produce annulated 1,4-cyclohexadienes possessing two stereogenic centers.