Two Distinct Cyclizations of 2‑Propenyl-1-ethynyl Benzenes with Aryldiazo Esters Using Au and Rh/Au Catalysts Respectively

This work reports the development of two catalytic cyclizations of 2-propenyl-1-ethynylbenzenes with aryldiazo esters. Cationic gold catalyst produces 2-substituted 3-alkenyl-1<i>H</i>-indenes with substrates over a reasonable scope. Our mechanistic study suggests that arydiazo esters attack at the cyclopropyl moieties of gold carbene intermediates, followed by skeletal rearrangement of resulting intermediates. In the presence of Rh₂(esp)₂ additive, the same gold catalyst alters the chemoselectivity of these reactants to afford tetrahydro-1<i>H</i>-cyclopropa­[<i>b</i>]­naphthalenes with excellent stereoselectivity. Herein, Rh­(II) catalyst catalyzed the reactions of the same 1,6-enynes with diazo species to form cyclopropenes initially, and a cationic Au­(I) catalyst allows their subsequent reactions with the tethered alkenes. Preferable <i>E</i>-selectivity and synergistic effects of Au/Rh catalysts are rationalized in a postulated mechanism

Synthetic Modification of Acyclic Bent Allenes (Carbodicarbenes) and Further Studies on Their Structural Implications and Reactivities

The paper describes the synthetic development of Bertrand-type acyclic carbodicarbene scaffolds derived from an unsymmetrical bis­(benzimidazol-2-yl)­methane bearing two sterically demanding pendant arms, isopropyl (<b>6a</b>) or cyclohexyl (<b>6b</b>). X-ray crystallographic analysis shows that the impact of these pendant arms on the overall structural parameters of carbodicarbenes is minimal. The chemical reactivity of the carbodicarbenes was evaluated with iodomethane to afford compound <b>7</b>, illustrating its nucleophilic properties. Finally, experiments were also undertaken to investigate the coordination ability of carbodicarbene toward the formation of rhodium carbonyl (<b>10</b>) and palladium allyl complexes (<b>11</b>). The crystal structures of the metal complexes have been determined, revealing that their metal–carbene distances are elongated only slightly, this fact was rationalized on the basis of geometrical steric considerations with regard to the ligand

Synthetic Modification of Acyclic Bent Allenes (Carbodicarbenes) and Further Studies on Their Structural Implications and Reactivities

The paper describes the synthetic development of Bertrand-type acyclic carbodicarbene scaffolds derived from an unsymmetrical bis­(benzimidazol-2-yl)­methane bearing two sterically demanding pendant arms, isopropyl (<b>6a</b>) or cyclohexyl (<b>6b</b>). X-ray crystallographic analysis shows that the impact of these pendant arms on the overall structural parameters of carbodicarbenes is minimal. The chemical reactivity of the carbodicarbenes was evaluated with iodomethane to afford compound <b>7</b>, illustrating its nucleophilic properties. Finally, experiments were also undertaken to investigate the coordination ability of carbodicarbene toward the formation of rhodium carbonyl (<b>10</b>) and palladium allyl complexes (<b>11</b>). The crystal structures of the metal complexes have been determined, revealing that their metal–carbene distances are elongated only slightly, this fact was rationalized on the basis of geometrical steric considerations with regard to the ligand

Blending Homopolymers for Controlling the Morphology Transitions of Block Copolymer Nanorods Confined in Cylindrical Nanopores

The microphase separation of block copolymers in confined geometries has been widely investigated over the last few decades. The controllability and versatility of the confinement-induced morphologies, however, are still difficult to be achieved because of the limited experimental parameters in the process of fabricating the confined nanostructures. In this work, we study the morphology transitions of lamellae-forming polystyrene-<i>block</i>-polydimethylsiloxane (PS-<i>b</i>-PDMS) nanorods confined in the nanopores of anodic aluminum oxide (AAO) templates. The nanorods are formed by solvent-assisted template wetting, and the morphologies are compared to those in the bulk state. By blending PS-<i>b</i>-PDMS with homopolystyrene (hPS), the morphologies of the nanorods can be controlled because of the changes of the effective volume fractions. Special morphology transitions from concentric lamellar morphology, to multihelical morphology, and finally to spherical-like morphology are observed by increasing the weight ratios of hPS. hPS with different molecular weights is also applied to investigate the effect of hPS on the morphologies of the PS-<i>b</i>-PDMS/hPS blend nanostructures. The unusual morphologies are further confirmed by a selective removal process, which also generates nanochannels for possible refilling with functional materials

The Elusive Three-Coordinate Dicationic Hydrido Boron Complex

The formation of a hitherto unknown three-coordinate dicationic hydrido boron complex is described. Interestingly, supporting ligand carbodicarbene gave unprecedented reaction with BH₃ without using more highly electrophilic Lewis acid precursors. Spectroscopic, crystallographic, and computational analysis was performed to understand the electronic features of these species

The Elusive Three-Coordinate Dicationic Hydrido Boron Complex

The formation of a hitherto unknown three-coordinate dicationic hydrido boron complex is described. Interestingly, supporting ligand carbodicarbene gave unprecedented reaction with BH₃ without using more highly electrophilic Lewis acid precursors. Spectroscopic, crystallographic, and computational analysis was performed to understand the electronic features of these species

Additional file 6: of Association of anticardiolipin, antiphosphatidylserine, anti-β2 glycoprotein I, and antiphosphatidylcholine autoantibodies with canine immune thrombocytopenia

Frequencies of aPL subtypes in all thrombocytopenic dogs. (PDF 47 kb

<em>R26R-GR</em>: A Cre-Activable Dual Fluorescent Protein Reporter Mouse

<div><p>Green fluorescent protein (GFP) and its derivatives are the most widely used molecular reporters for live cell imagining. The development of organelle-specific fusion fluorescent proteins improves the labeling resolution to a higher level. Here we generate a <em>R26</em> dual fluorescent protein reporter mouse, activated by Cre-mediated DNA recombination, labeling target cells with a chromatin-specific enhanced green fluorescence protein (EGFP) and a plasma membrane-anchored monomeric cherry fluorescent protein (mCherry). This dual labeling allows the visualization of mitotic events, cell shapes and intracellular vesicle behaviors. We expect this reporter mouse to have a wide application in developmental biology studies, transplantation experiments as well as cancer/stem cell lineage tracing.</p> </div

Endoplasmic reticulum (ER) and endosomes labeled by mCherry-GPI in the intestinal epithelia of a P21 heterozygous <i>R26-GR</i> pup.

<p>Immunohistochemistry using antibodies against a endosome-specific marker (EEA-1)(top row) and an ER-specific marker (calnexin) (bottom row) provides signals coincided with mCherry-GPI distributions (arrows). Scale bar: 5 µm.</p

Ubiquitous dual fluorescent protein reporter expression from <i>R26</i> resulting from a <i>Sox2Cre</i>-mediated activation event.

<p>The <i>R26R-GR</i> male is crossed with a female <i>Sox2Cre</i> transgenic mouse to obtain compound heterozygous progeny with the dual fluorescent protein reporter activated in all tissues of an E10.5 embryo. (A, B, C) Whole mount images of E10.5 heterozygous <i>R26R-GR</i> (left) and <i>Sox2Cre</i>-activated <i>R26R-GR</i> (right) embryos under a fluorescent dissection microscope. The inactivated <i>R26R-GR</i> embryo shows neither EGFP nor mCherry signals whereas the compound heterozygous <i>Sox2Cre/+; R26R-GR/+</i> embryo emits both green and red lights throughout the body. Scale bar: 1 mm. (D, E, F) Cross section of a E10.5 <i>Sox2Cre/+; R26R-GR/+</i> embryo reveals ubiquitous expression of a nucleus localized EGFP and a cell membrane bound mCherry. Scale bar: 75 µm. (G, H, I) Higher magnifications from D–F pictures are shown. Scale bar: 25 µm.</p