نتایج جستجو برای: trans and vinyl
تعداد نتایج: 16841581 فیلتر نتایج به سال:
The first enantioselective cross-electrophile coupling of aryl bromides with meso-epoxides to form trans-β-arylcycloalkanols is presented. The reaction is catalyzed by a combination of (bpy)NiCl2 and a chiral titanocene under reducing conditions. Yields range from 57 to 99% with 78-95% enantiomeric excess. The 30 examples include a variety of functional groups (ether, ester, ketone, nitrile, ke...
We report the discovery of two unsaturated organic species, trans-(E)-cyanovinylacetylene and vinylcyanoacetylene, using second data release GOTHAM deep survey towards TMC-1 with 100 m Green Bank Telescope. For both detections, we performed velocity stacking matched filter analyses Markov chain Monte Carlo simulations, for trans-(E)-cyanovinylacetylene, three rotational lines were observed at l...
THE TITLE COMPOUND [SYSTEMATIC NAME: (1R,4aR,7S,8aS,10aS)-1,4a,7-trimethyl-7-vinyl-1,2,3,4,4a,6,7,8,8a,9,10,10a-dodeca-hydro-phenanthrene-1-carb-oxy-lic acid], C(20)H(30)O(2), is a pimarane-type diterpene extracted from Croton oblongifolius. There are two independent mol-ecules in the asymmetric unit. In both of these, the six-membered rings A, B and C adopt chair, boat and half-chair conformat...
The hydroauration of internal and terminal alkynes by gold(III) hydride complexes [(C^N^C)AuH] was found to be mediated by radicals and proceeds by an unexpected binuclear outer-sphere mechanism to cleanly form trans-insertion products. Radical precursors such as azobisisobutyronitrile lead to a drastic rate enhancement. DFT calculations support the proposed radical mechanism, with very low act...
In the title compound, C36H36N2, a product of the condensation reaction of 2,3-dimethyl-6-phenyl-vinyl-benzenamine and 2,3-butane-dione, the complete mol-ecule is generated by the application of an inversion centre. The central C-C bond in the 1,4-di-aza-butadiene fragment is trans-configured and situated about the inversion center. The dihedral angle between the ring attached to N and the 1,4-...
The Poly (vinyl alcohol)/Kefirane nanofiber membrane was successfully fabricated for the firsttime using electrospinning of the polyvinyl alcohol (PVA) and Kefirane blend solution. Scanningelectron microscope (SEM), attenuated total reflectance Fourier transform infrared (ATRFT-IR), and differential scanning calorimetry (DSC) were used to characterize the electrospunPoly (vinyl alcohol)/Kefiran...
Vertical excitation energies and oscillator strengths for several valence and Rydberg electronic states of vinyl, propen-1-yl, propen-2-yl, 1-buten-2-yl, and trans-2-buten-2-yl radicals are calculated using the equation-of-motion coupled cluster methods with single and double substitutions (EOM-CCSD). The ground and the lowest excited state (n <-- pi) equilibrium geometries are calculated using...
Chiral acrylic esters derived from biomass were developed as models to have a better insight in the aryl-vinyl π-stacking interactions. Quantum chemical calculations, NMR studies and experimental evidences demonstrated the presence of equilibriums of at least four different conformations: π-stacked and face-to-edge, each of them in an s-cis/s-trans conformation. The results show that the stabil...
Flash vacuum pyrrolysis of vinyl epoxides provides cis-dihydrofuran carboxylic esters in good yields and diastereoselectivities, which, on base-promoted epimerisation afford the complementary trans series. The compounds provide a viable template for a Lewis acid promoted cyclisation to provide the 2,6-diaryl-3,7-dioxabicyclo[3.3.0]octane core found in the furofuran series of natural lignans. Th...
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