Synthesis of Poly(arylenevinylene)s by Rhodium-Catalyzed Stitching Polymerization/Alkene Isomerization

Poly­(arylenevinylene)­s constitute an important class of π-conjugated polymers for their potential utility as optoelectronic materials. Herein, we developed a sequence of rhodium-catalyzed stitching polymerization of 1,2-dialkynyl­(hetero)­arenes and aromatization-driven alkene isomerization for the synthesis of new poly­(arylenevinylene)­s. The polymerization and subsequent alkene isomerization proceeded smoothly with high degree of stitching efficiency by employing a Rh/tfb complex as the catalyst, and not only diynes but also triynes and tetraynes could be polymerized to give poly­(arylenevinylene)­s that are not easily accessible by existing synthetic methods. The polymers obtained by the present method were thermally stable, and their optical properties could be varied depending on the repeating unit structure

Copper-Catalyzed Hydroboration of Carbon Dioxide

A copper/N-heterocyclic carbene catalyzed hydroboration of carbon dioxide has been developed to give a formic acid derivative selectively under mild conditions. Investigations directed toward understanding the catalytic cycle of this process have been carried out, and the hydroboration product can be directly used as a formylation reagent for various amines

Rhodium-Catalyzed Stitching Reaction: Convergent Synthesis of Quinoidal Fused Oligosiloles

Quinoidal fused oligosiloles, a new family of silicon-bridged π-conjugated compounds, have been synthesized for the first time based on a new synthetic strategy, a stitching reaction. Multiple carbon–carbon bonds can be formed consecutively between two oligo­(silylene-ethynylene)­s under rhodium catalysis in a stitching manner, and up to five siloles have been fused in a quinoidal form. Physical properties of these oligosiloles have also been investigated to find a unique trend in their LUMO levels, which become higher with longer π-conjugation

Rhodium-Catalyzed Polymerization of 3,3-Diarylcyclopropenes Involving a 1,4-Rhodium Migration

A new mode of metal-catalyzed polymerization reaction has been developed by exploiting the ability of 1,4-rhodium migration of an organorhodium­(I) species. Specifically, it has been demonstrated that 3,3-diarylcyclopropenes undergo polymerization through an insertion–1,4-rhodium migration sequence by using an arylrhodium­(I) initiator/catalyst to give poly­(cyclopropylene-<i>o</i>-phenylene)­s, which are difficult to synthesize by conventional polymerization methods

Rhodium-Catalyzed Stitching Reaction: Convergent Synthesis of Quinoidal Fused Oligosiloles

Quinoidal fused oligosiloles, a new family of silicon-bridged π-conjugated compounds, have been synthesized for the first time based on a new synthetic strategy, a stitching reaction. Multiple carbon–carbon bonds can be formed consecutively between two oligo­(silylene-ethynylene)­s under rhodium catalysis in a stitching manner, and up to five siloles have been fused in a quinoidal form. Physical properties of these oligosiloles have also been investigated to find a unique trend in their LUMO levels, which become higher with longer π-conjugation

The quality of information support analysis of business enterprises

В публікації розглядається основні характеристики інформаційного забезпечення діяльності підприємства.This publication is considered the main characteristics of the enterprise information supply

Palladium-Catalyzed Desymmetrization of Silacyclobutanes with Alkynes: Enantioselective Synthesis of Silicon-Stereogenic 1-Sila-2-cyclohexenes and Mechanistic Considerations

A palladium-catalyzed enantioselective desymmetrization of silacyclobutanes with alkynes has been developed to give silicon-stereogenic 1-sila-2-cyclohexenes with high enantioselectivity. The products thus obtained undergo further derivatizations with complete stereoselectivity, and a new catalytic cycle involving alkyne coordination (oxidative cyclization)–transmetalation (σ-bond metathesis)–reductive elimination has also been proposed

Palladium-Catalyzed Desymmetrization of Silacyclobutanes with Alkynes: Enantioselective Synthesis of Silicon-Stereogenic 1-Sila-2-cyclohexenes and Mechanistic Considerations

A palladium-catalyzed enantioselective desymmetrization of silacyclobutanes with alkynes has been developed to give silicon-stereogenic 1-sila-2-cyclohexenes with high enantioselectivity. The products thus obtained undergo further derivatizations with complete stereoselectivity, and a new catalytic cycle involving alkyne coordination (oxidative cyclization)–transmetalation (σ-bond metathesis)–reductive elimination has also been proposed

Palladium-Catalyzed Synthesis of 4-Oxaspiro[2.4]heptanes via Central Attack of Oxygen Nucleophiles to π-Allylpalladium Intermediates

A palladium-catalyzed decarboxylative cyclopropanation of γ-methylidene-δ-valerolactones with aromatic aldehydes has been developed to give 4-oxaspiro[2.4]heptanes with high selectivity. The site of nucleophilic attack to a π-allylpalladium intermediate has been controlled with a sterically demanding phosphine ligand. The course of the reaction is highly dependent on ligands and solvents, and selective formation of methylenetetrahydropyrans has also been realized

Intermolecular Three-Component Arylsilylation of Alkynes under Palladium/Copper Cooperative Catalysis

An intermolecular three-component arylsilylation of alkynes has been developed under mild palladium/copper cooperative catalysis. The reaction proceeds through <i>syn</i>-addition of an aryl group and a silyl group across the carbon–carbon triple bond of an alkyne. This represents the first transition-metal-catalyzed fully intermolecular arylsilylation of alkynes, and transformations of the resulting products have also been demonstrated