Hajime Ito

Reversible mechanochromic luminescence of [(C6F5Au)2(mu-1,4-diisocyanobenzene)] is reported. Grinding of the complex induced a photoluminescent color change, which was restored by exposure to a solvent. This cycle was repeated 20 times with no color degradation in the emissions. Their optical properties, X-ray crystallographic analysis, IR, and XRD measurements strongly suggested that the change in the molecular arrangement is responsible for this mechanochromic property. Intermolecular aurophil

This review is a guided tour along the activation modes and reactivity of B-B, B-Si, B-N, B-S, B-Se and B-P reagents, in the absence of any transition metal complex. Here are disclosed the general concepts related to the homolytic and heterolytic cleavage of B-B and B-interelement bonds, as well as the generation of new C-B and C-interelement bonds, in a selective way. The greener consequences of these novel routes facilitate the gram scale preparations of target functionalised organic compounds

A method for the synthesis of alpha-chiral allylboronates featuring the Cu(I)-catalyzed enantioselective substitution of readily available allylic carbonates with a diboron is described. Using this method, various alpha-chiral allylboronates, including functionalized allylboronates, were successfully synthesized, with high enantiomeric purity.

We report the first laser spectroscopic experiments on the Rb beam guided by blue-detuned evanescent waves in micron-sized hollow fibers. The two-step photoionization spectra show the long-range dispersive properties of dipole interaction between guided atoms and evanescent waves. A large enhancement factor of 20 in in the transmitted atomic flux is obtained at optimal conditions and the total guidance efficiency is estimated to be above 40%. The state- and species-selective guide with proper fr

Two for the show: A copper(I)-catalyzed reaction forms boron–silicon bifunctional cyclopropane derivatives from γ-silylated allylic carbonates and a diboron species (see scheme). The reaction is highly enantioselective when a chiral bisphosphine ligand is used. The stereoelectronic effect of the silyl group induces unusual regioselectivity of the borylcopper(I) addition across the CC double bond. Supporting information for this article is available on the WWW under http://www.wiley-vch.de/conte

Borylation of alkyl halides with diboron proceeded in the presence of a copper(I)/Xantphos catalyst and a stoichiometric amount of K(O-t-Bu) base. The boryl substitution proceeded with normal and secondary alkyl chlorides, bromides, and iodides, but alkyl sulfonates did not react. Menthyl halides afforded the corresponding borylation product with excellent diastereoselectivity, whereas (R)-2-bromo-5-phenylpentane gave a racemic product. Reaction with cyclopropylmethyl bromide resulted in ring-op

A copper-catalyzed gamma-selective and stereospecific substitution reaction of allylic carbonates with a diboron reagent affording allylboron compounds is described. Boryl group was selectively introduced at the gamma-position of the leaving carbonate group. Functionalized allylboronates that have an acetal, ester, or isolated alkene were prepared. The reaction of optically active allylic carbonates underwent complete alpha-to-gamma chirality transfer with anti-stereochemistry to produce optical

A copper(I)-catalyzed stereospecific reaction for the preparation of cis- and trans-1-silyl-2-borylcyclobutanes as well as 1-phenyl-2-borylcyclobutanes is reported. (Z)- and (E)-Homoallylic methanesulfonates were converted to the corresponding trans- and cis-cyclobutane derivatives, respectively, in the presence of a CuCl/dppp catalyst, bis(pinacolato)diboron, and K(O-t-Bu)/THF. Stereospecific derivatizations of the cis- and trans-borylcyclobutanes were carried out to demonstrate the utility of

A versatile synthetic method for the preparation of the allenylboronates, Cu(I)-catalyzed reaction of propargylic carbonates with a diboron, is described. A Cu(O-t-Bu)-Xantphos catalyst system was effective for the preparation of various allenylboron compounds, allenylboronates with different substitution patterns, those with functional groups, and an axially chiral one. The Lewis acid promoted stereoselective addition to aldehydes leading to homopropargylic alcohols showed the usefulness of the

Hooray for hydroboration! The products afforded by the title reaction depend on the substitution pattern on the double bond moiety of 1,3-enyne substrates (see scheme). These types of products, either 1,3-dienylboronates or 3-alkynylboronates, are difficult to obtain by other methods. Interestingly, ligand-controlled borylation was observed with high selectivity in some cases. pin=pinacolato, THF=tetrahydrofuran. Detailed facts of importance to specialist readers are published as ”Supporting Inf

The first catalytic enantioselective γ-boryl substitution of CF₃ -substituted alkenes is reported. A series of CF₃ -substituted alkenes was treated with a diboron reagent in the presence of a copper(I)/Josiphos catalyst to afford the corresponding optically active γ,γ-gem-difluoroallylboronates in high enantioselectivity. The thus obtained products could be readily converted into the corresponding difluoromethylene-containing homoallylic alcohols using highly stereospecific

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTInteractions in mixtures of poly(ethylene oxide) and poly(methyl methacrylate)H. Ito, T. P. Russell, and G. D. WignallCite this: Macromolecules 1987, 20, 9, 2213–2220Publication Date (Print):September 1, 1987Publication History Published online1 May 2002Published inissue 1 September 1987https://pubs.acs.org/doi/10.1021/ma00175a028https://doi.org/10.1021/ma00175a028research-articleACS PublicationsRequest reuse permissionsArticle Views742Altmetric-Citati