38440-26-5Relevant articles and documents
Efficient synthesis of bicyclo[6.3.0]undecadienones by Nazarov cyclization/regioselective elimination
Matier, Carson D.,Kwon, Yonghoon,West
, p. 58 - 61 (2014)
Easily accessible cyclooctadienyl vinyl ketones can generate fused bicyclic 8-5 (bicyclo[6.3.0]undecadienone) ring systems via the Nazarov cyclization when treated with Lewis acid. The resultant products contain three new stereocenters as well as olefins suitably situated to allow further structural elaboration. This concise sequence allows for the rapid preparation of intermediates that should be applicable to a variety of natural product targets containing this bicyclic core.
Reactions of Sodium Diisopropylamide: Liquid-Phase and Solid-Liquid Phase-Transfer Catalysis by N, N, N′, N″, N″-Pentamethyldiethylenetriamine
Ma, Yun,Woltornist, Ryan A.,Algera, Russell F.,Collum, David B.
supporting information, p. 13370 - 13381 (2021/09/03)
Sodium diisopropylamide (NaDA) in N,N-dimethylethylamine (DMEA) and DMEA-hydrocarbon mixtures with added N,N,N′,N″,N″-pentamethyldiethylenetriamine (PMDTA) reacts with alkyl halides, epoxides, hydrazones, arenes, alkenes, and allyl ethers. Comparisons of PMDTA with N,N,N′,N′-tetramethylethylenediamine (TMEDA) accompanied by detailed rate and computational studies reveal the importance of the trifunctionality and κ2-κ3 hemilability. Rate studies show exclusively monomer-based reactions of 2-bromooctane, cyclooctene oxide, and dimethylresorcinol. Catalysis with 10 mol % PMDTA shows up to >30-fold accelerations (kcat > 300) with no evidence of inhibition over 10 turnovers. Solid-liquid phase-transfer catalysis (SLPTC) is explored as a means to optimize the catalysis as well as explore the merits of heterogeneous reaction conditions.
Covalent Post-assembly Modification Triggers Multiple Structural Transformations of a Tetrazine-Edged Fe4L6 Tetrahedron
Roberts, Derrick A.,Pilgrim, Ben S.,Sirvinskaite, Giedre,Ronson, Tanya K.,Nitschke, Jonathan R.
supporting information, p. 9616 - 9623 (2018/07/21)
Covalent post-assembly modification (PAM) reactions are useful synthetic tools for functionalizing and stabilizing self-assembled metal-organic complexes. Recently, PAM reactions have also been explored as stimuli for triggering supramolecular structural transformations. Herein we demonstrate the use of inverse electron-demand Diels-Alder (IEDDA) PAM reactions to induce supramolecular structural transformations starting from a tetrazine-edged FeII4L6 tetrahedral precursor. Following PAM, this tetrahedron rearranged to form three different architectures depending on the addition of other stimuli: an electron-rich aniline or a templating anion. By tracing the stimulus-response relationships within the system, we deciphered a network of transformations that mapped different combinations of stimuli onto specific transformation products. Given the many functions being developed for self-assembled three-dimensional architectures, this newly established ability to control the interconversion between structures using combinations of different stimulus types may serve as the basis for switching the functions expressed within a system.
Efficient Synthesis of Amines by Iron-Catalyzed C=N Transfer Hydrogenation and C=O Reductive Amination
Facchini, Sofia Vailati,Cettolin, Mattia,Bai, Xishan,Casamassima, Giuseppe,Pignataro, Luca,Gennari, Cesare,Piarulli, Umberto
, p. 1054 - 1059 (2018/01/27)
Here we report the catalytic transfer hydrogenation (CTH) of non-activated imines promoted by a Fe-catalyst in the absence of Lewis acid co-catalysts. Use of the (cyclopentadienone)iron complex 1, which is much more active than the classical ‘Kn?lker complex’ 2, allowed to reduce a number of N-aryl and N-alkyl imines in very good yields using iPrOH as hydrogen source. The reaction proceeds with relatively low catalyst loading (0.5–2 mol%) and, remarkably, its scope includes also ketimines, whose reduction with a Fe-complex as the only catalyst has little precedents. Based on this methodology, we developed a one-pot CTH protocol for the reductive amination of aldehydes/ketones, which provides access to secondary amines in high yield without the need to isolate imine intermediates. (Figure presented.).
Engaging Alkenyl Halides with Alkylsilicates via Photoredox Dual Catalysis
Patel, Niki R.,Kelly, Christopher B.,Jouffroy, Matthieu,Molander, Gary A.
supporting information, p. 764 - 767 (2016/03/01)
Single-electron transmetalation via photoredox/nickel dual catalysis provides the opportunity for the construction of Csp3-Csp2 bonds through the transfer of alkyl radicals under very mild reaction conditions. A general procedure for the cross-coupling of primary and secondary (bis-catecholato)alkylsilicates with alkenyl halides is presented. The developed method allows not only alkenyl bromides and iodides but also previously underexplored alkenyl chlorides to be employed. (Chemical Equation Presented).
Organic photoredox catalysis for the oxidation of silicates: Applications in radical synthesis and dual catalysis
Lévêque, Christophe,Chenneberg, Ludwig,Corcé, Vincent,Ollivier, Cyril,Fensterbank, Louis
supporting information, p. 9877 - 9880 (2016/08/11)
Metal free photooxidation of alkyl bis(catecholato)silicates with the organic dye 1,2,3,5-tetrakis(carbazol-9-yl)-4,6-dicyano-benzene (4CzIPN) allows the smooth formation of alkyl radicals. The latter can be efficiently engaged either with radical acceptors to provide homolytic addition products or in photoredox/nickel dual catalysis reactions to obtain cross-coupling products.
Electronic effects versus distortion energies during strain-promoted alkyne-azide cycloadditions: A theoretical tool to predict reaction kinetics
Garcia-Hartjes, Jaime,Dommerholt, Jan,Wennekes, Tom,Van Delft, Floris L.,Zuilhof, Han
supporting information, p. 3712 - 3720 (2013/07/26)
Second-order reaction kinetics of known strain-promoted azide-alkyne cycloaddition (SPAAC) reactions were compared with theoretical data from a range of ab initio methods. This produced both detailed insights into the factors determining the reaction rates and two straightforward theoretical tools that can be used to predict a priori the reaction kinetics of novel cyclooctynes for strain-promoted cycloaddition reactions. Multiple structural and electronic effects contribute to the reactivity of various cyclooctynes. It is therefore hard to relate a physical or electronic property directly and independently to the reactivity of the cyclooctyne. However, we show that Hartree-Fock LUMO energies, which were acquired while calculating activation energies at the MP2 level of theory, correlate with second-order kinetic rate data and are therefore usable for reactivity predictions of cyclooctynes towards azides. Using this correlation, we developed a simple theoretical tool that can be used to predict the reaction kinetics of (novel) cyclooctynes for SPAAC reactions. Activation energies, distortion energies, and TS conformational data were compared in a set of strained cyclooctynes in strain-promoted azide-alkyne cycloaddition (SPAAC) reactions. Only electronic effects could be accurately related to experimental rate data. Copyright
Formation of enehydrazine intermediates through coupling of phenylhydrazines with vinyl halides: Entry into the Fischer indole synthesis
Zhan, Fuxu,Liang, Guangxin
supporting information, p. 1266 - 1269 (2013/03/13)
Cut to the chase: Direct formation of an enehydrazine, an intermediate in the classic Fischer indole synthesis, solves the regioselectivity problem associated with indolization. This approach not only achieves selective synthesis of indoles through proper selection of the vinyl halide, but also leads to quick construction of desoxyeseroline and esermethole, as well as the key structural motif in the Akuammiline alkaloid vincorine. Copyright
Clicking 1,2,4,5-tetrazine and cyclooctynes with tunable reaction rates
Chen, Weixuan,Wang, Danzhu,Dai, Chaofeng,Hamelberg, Donald,Wang, Binghe
supporting information; experimental part, p. 1736 - 1738 (2012/03/09)
Substituted tetrazines have been found to undergo facile inverse electron demand Diels-Alder reactions with "tunable" reaction rates.
Pushing the σ-donor strength in iridium pincer complexes: Bis(silylene) and bis(germylene) ligands are stronger donors than bis(phosphorus(III)) ligands
Brueck, Andreas,Gallego, Daniel,Wang, Wenyuan,Irran, Elisabeth,Driess, Matthias,Hartwig, John F.
, p. 11478 - 11482 (2013/01/15)
Breaking the donor limits: The remarkable coordination chemistry of ECHE (E=Si, Ge) ligands with Group-9 metals (Ir, Rh) and their application in catalytic C-H borylation of arenes was investigated. The spectroscopic and structural features of the first [ECE] iridium complexes show the stronger σ-donating properties of the divalent Si and Ge pincer ligands compared to analogous PIII-based ligands. Copyright
