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We report a tri-n-butyl phosphine catalyzed regio- and stereo-selective hydroboration of ynamides to yield (Z)-β-borylenamides in good yields. Surprisingly, a formal cis addition to the triple bond was observed as confirmed by NMR and X-ray crystallography. 31P NMR studies suggest that a zwitterionic vinylphosphonium intermediate is key in the mechanism. The resulting products were further transformed to β-CF3 enamides via stereoretentive trifluoromethylation. [ABSTRACT FROM AUTHOR]

We report an organocatalytic trans hydroboration of 3-substituted-propiolonitriles. In the presence of catalytic amounts of tributylphosphine and pinacolborane, regioselective hydroboration of the internal triple bond proceeded in a stereoselective fashion under mild conditions to afford the corresponding (E)-1,2-vinylcyanoborane derivatives. The mechanism is proposed to occur through a 1,2-phosphine addition instead of a canonical 1,4-conjugate addition pathway. [ABSTRACT FROM AUTHOR]

A method has been developed for the facile Cu(II)-catalyzed protoboration of monosubstituted allenes in aqueous media under atmospheric conditions. The reaction occurs site selectively, favoring internal alkene protoboration to afford 1,1-disubstituted vinylboronic acid derivatives (up to 93 : 7) with modest to good yields. The method has been applied to a variety of phenylallene derivatives as well as alkylsubstituted allenes. [ABSTRACT FROM AUTHOR]

The diboration of substituted propargylic alcohols has been achieved using a bimetallic Pd/Cu catalyst system. The in situ formation of a pentrafluoroboronic acid intermediate sufficiently activates the C–O bond towards dual catalysis affording (Z)-allyl, vinyldiboronates stereoselectively. [ABSTRACT FROM AUTHOR]

Organoboron compounds are valuable synthetic intermediates that find application in a diverse variety of processes including both C-X and C-C bond-forming transformations. This has been achieved by using a variety of boron derivatives. Of these, boronate esters are probably the most versatile and, reflecting this, methods for the generation of boronate esters are of considerable current interest. Given the mild reaction conditions, good functional group tolerance, and low cost of the metal catalyst, the use of copper-boryl reagents is particularly attractive. In this review, methodologies in copper-boryl chemistry are discussed and the many different transformations possible are surveyed. [ABSTRACT FROM AUTHOR]

Cancer progression and physiological changes within the cells are accompanied by alterations in the biophysical properties. Therefore, the cell biophysical properties can serve as promising markers for cancer detection and physiological activities. To aid in the investigation of the biophysical markers of cells, a microfluidic chip has been developed which consists of a constriction channel and embedded microelectrodes. Single-cell impedance magnitudes at four frequencies and entry and travel times are measured simultaneously during their transit through the constriction channel. This microchip provides a high-throughput, label-free, automated assay to identify biophysical signatures of malignant cells and monitor the therapeutic efficacy of drugs. Here, we monitored the dynamic cellular biophysical properties in response to sphingosine kinase inhibitors (SphKIs), and compared the effectiveness of drug delivery using poly lactic-co-glycolic acid (PLGA) nanoparticles (NPs) loaded with SphKIs versus conventional delivery. Cells treated with SphKIs showed significantly higher impedance magnitudes at all four frequencies. The bioelectrical parameters extracted using a model also revealed that the highly aggressive breast cells treated with SphKIs shifted electrically towards that of a less malignant phenotype; SphKI-treated cells exhibited an increase in cell-channel interface resistance and a significant decrease in specific membrane capacitance. Furthermore, SphKI-treated cells became slightly more deformable as measured by a decrease in their channel entry and travel times. We observed no significant difference in the bioelectrical changes produced by SphKI delivered conventionally or with NPs. However, NPs-packaged delivery of SphKI decreased the cell deformability. In summary, this study showed that while the bioelectrical properties of the cells were dominantly affected by SphKIs, the biomechanical properties were mainly changed by the NPs. [ABSTRACT FROM AUTHOR]

We report branched peptide boronic acids (BPBAs) that bind to RRE IIB from an on-bead high-throughput screening of a 3.3.4-library (46 656 compounds). We demonstrate that boronic acids are tunable moieties that afford a novel binding mode towards RNA. [ABSTRACT FROM AUTHOR]

A mild and efficient copper-catalyzed borylation of electron deficient allenoates using an sp2–sp3mixed hybridized diboron regioselectively installs a boron moiety on the β-position with exclusive (Z)-double bond geometry. [ABSTRACT FROM AUTHOR]

High throughput screening of a 4096 compound library of boronic acid and acridine containing branched peptides revealed compounds that have dissociation constants in the low nanomolar regime for HIV-1 RRE IIB RNA. We demonstrate that branched peptide boronic acids A5 , A6 , and A7 inhibit the production of p24, an HIV-1 capsid protein, in a dose-dependent manner.

A simple and robust solid phase synthetic method for the ligation of diamondoids on the phosphate backbone of DNA with "click" chemistry using [Cu(CH(3)CN)(4)]PF(6) without a stabilizing ligand is reported. It was found that as the size of dimondoid increased, a corresponding increase in melting temperature was observed., (This journal is © The Royal Society of Chemistry 2012)

A mild and efficient copper-catalyzed borylation of electron deficient allenoates using an sp(2)-sp(3) mixed hybridized diboron regioselectively installs a boron moiety on the β-position with exclusive (Z)-double bond geometry.