RhIII-catalyzed C−H functionalization reaction yielding isoindolinones from aryl hydroxamates and ortho-substituted styrenes is reported. The reaction proceeds smoothly under mild conditions at room temperature, and tolerates a range of functional groups. Experimental and computational investigations support that the high regioselectivity observed for these substrates results from the presence of an ortho-substituent embedded in the styrene. The resulting isoindolinones are valuable building blocks for the synthesis of bioactive compounds. They provide easy access to the natural-product-like compounds, isoindolobenzazepines, in a one-pot two-step reaction. Selected isoindolinones inhibited Hedgehog (Hh)-dependent differentiation of multipotent murine mesenchymal progenitor stem cells into osteoblasts. 相似文献
Contrary to previous results hex-2-enopyranosyl trichloroacetimidates do not rearrange to amino-branched glycals but give N-acylated hex-2-enopyranosyl amines. 相似文献
The pervasiveness of multi-stability in nonlinear dynamical systems calls for novel concepts of stability and a consistent quantification of long-term behavior. The basin stability is a global stability metric that builds on estimating the basin of attraction volumes by Monte Carlo sampling. The computation involves extensive numerical time integrations, attractor characterization, and clustering of trajectories. We introduce bSTAB, an open-source software project that aims at enabling researchers to efficiently compute the basin stability of their dynamical systems with minimal efforts and in a highly automated manner. The source code, available at https://github.com/TUHH-DYN/bSTAB/, is available for the programming language Matlab featuring parallelization for distributed computing, automated sensitivity and bifurcation analysis as well as plotting functionalities. We illustrate the versatility and robustness of bSTAB for four canonical dynamical systems from several fields of nonlinear dynamics featuring periodic and chaotic dynamics, complicated multi-stability, non-smooth dynamics, and fractal basins of attraction. The bSTAB projects aims at fostering interdisciplinary scientific collaborations in the field of nonlinear dynamics and is driven by the interaction and contribution of the community to the software package.
Nickel Complexes of Mercaptoacetic Acid The reaction of [Cp°2Zr(OOCCH2SH‐κ1O)(OOCCH2SH‐κ2O, O′)] (Cp° = C5EtMe4) with [NiCl2(PMe2Ph)2] or [NiCl2(dppe)] (dppe = PPh2CH2CH2PPh2) in the presence of NEt3 yields the tetranuclear ZrIV/NiII complex [{Cp°2Zr(κ1O‐OOCCH2S‐κ2O′, S)(κ2O, O′‐OOCCH2S‐κ1S)Ni(PMe2Ph)}2] ( 1 ) and the chelate complexes [Ni(OOCCH2S‐κ2O, S)L2] [L = PMe2Ph ( 2 ), L2 = dppe ( 3 )]. 2 and 3 are also accessible from [NiCl2(PMe2Ph)2] or [NiCl2(dppe)] and mercaptoacetic acid in the presence of NEt3 in quantitative yield. The structure of 2 is dynamic in solution, whereby a complex with three‐coordinate nickel atom is formed. 2 and 3 were characterized spectroscopically (1H, 13C, 31P NMR and IR) and by crystal structure determination. 相似文献
Stabilization of chiral propeller conformations in triaryl compounds is challenging due to generally low racemization barriers. Nonetheless, it was recently found that chiral conformational preferences can be induced to triaryl boranes by incorporating point-chiral alkylether chains to the aryl blades and subsequently locking the structure with ammonia. A four-point interaction, meaning that the cooperative effects of Lewis-adduct formation and three hydrogen bonds, was proposed as stabilizing mechanism. Herein, it was shown that three such strong interactions suffice to introduce a preferential propeller handedness. Although DFT calculations predict no noteworthy preferences for either P- or M-chiral propellers for some of the investigated triarylborane–amine adducts that were prepared with chiral primary amines, vibrational circular dichroism (VCD) spectroscopic characterizations revealed that there is indeed a measurable excess of one propeller handedness. Furthermore, the steric demand of the amine was found to play a key role in the induction process and especially in preventing blade rotations. 相似文献
In the present work, the first observation of strong resonance Raman optical activity (RROA) involving more that one resonant electronic state is reported. The chiral transition metal complex bis-(trifluoroacetylcamphorato) copper(II), abbreviated Cu(tfc)(2), exhibits both resonance Raman (RR) and RROA spectra with laser excitation at 532 nm. Vibrational assignments for this complex were carried out by comparing the non-RR spectra of Cu(tfc)(2) excited at 1024 nm to density functional theory (DFT) calculations. The theory of the single-electronic-state (SES) RROA is extended to the next simplest level of theory involving two resonant electronic states (TES) without interstate vibronic coupling as an aide to the interpretation of the observed TES-RROA spectra. Based on measured UV-vis electronic absorbance spectra and corresponding TD-DFT calculations, the most likely two states associated with the RROA spectra are identified. 相似文献
Methods permitting to test the influence of the matrix as well as of its local and temporal distribution on the plasma conditions in laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS) are developed. For this purpose, the MS interface is used as plasma probe allowing to investigate the average plasma condition within the ICP zone observed in terms of temporal and spatial distribution of the matrix. 相似文献