使用顺磁性钴(II)卟啉催化剂[Co II (TPP)](TPP=四苯基卟啉)对邻烯丙基羰基-芳基N-芳基磺酰腙进行金属自由基活化,为合成新型8元杂环化合物提供了一种有效且强大的方法烯醇醚。该合成方案通用且实用,能够以高产率合成多种独特的 1 H -2-苯并氧辛。催化环化反应具有优异的化学选择性,具有较高的官能团耐受性,并为合成新的生物活性化合物提供了多种机会。该反应通过钴(III)-卡宾自由基中间体进行,该中间体参与从烯丙基位置到卡宾自由基的分子内氢转移(HAT),然后在钴的配位层中进行近无障碍的自由基反弹步骤。所提出的机制得到了实验观察、密度泛函理论(DFT)计算和自旋捕获实验的支持。
Hypervalent iodine(<scp>iii</scp>) induced oxidative olefination of benzylamines using Wittig reagents
作者:Vijayalakshmi Ramavath、Bapurao D. Rupanawar、Satish G. More、Ajay H. Bansode、Gurunath Suryavanshi
DOI:10.1039/d1nj01170g
日期:——
and secondary benzylamines using 2C-Wittig reagents, which provides easyaccess to α,β-unsaturated esters. Mild reaction conditions, good to excellent yields with high (E) selectivity, and a broad substrate scope are the key features of this reaction. We have successfully carried out the gram-scale synthesis of α,β-unsaturated esters.
Photoenzymatic Generation of Unstabilized Alkyl Radicals: An Asymmetric Reductive Cyclization
作者:Phillip D. Clayman、Todd K. Hyster
DOI:10.1021/jacs.0c07918
日期:2020.9.16
Flavin-dependent 'ene'-reductases (ERED) can generate stabilized alkyl radicals when irradiated with visible light, however, they are not known to form unstabilized radicals. Here, we report an enantioselective radical cyclization using alkyl iodides as precursors to unstabilized nucleophilic radicals. Evidence suggests this species is accessed by photoexcitation of a charge-transfer complex that forms between flavin
Rhodium(III)-catalyzed annulative coupling of sulfoxonium ylides with allenoates was achieved, forming highly functionalized cyclopropanes with a quaternary carbon center by means of the sulfoxonium ylide functionality as a traceless bifunctional directinggroup and C4 synthon via an arene C-H activation and cyclopropanation cascade. The protocol features simultaneous formation of three new C-C bonds
Described herein are peptide derivatives and peptidomimetics as inhibitors for transglutaminases, methods for their preparation, pharmaceutical compositions containing said compounds as well as uses of said transglutaminase inhibitors in particular for the treatment of coeliac disease and transglutaminase dependent diseases.
Flash vacuum pyrolysis of alkoxycarbonyl/sulfinyl stabilised phosphorus ylides: generation and intramolecular insertion of alkoxycarbonyl(sulfenyl)carbenes
作者:R. Alan Aitken、Martin J. Drysdale、Bruce M. Ryan
DOI:10.1039/c39940000805
日期:——
Flashvacuumpyrolysis of phosphorus ylides stabilised both by ester and sulfinyl groups results mainly in extrusion of Ph3PO to generate alkoxycarbonyl(sulfenyl)carbenes; these undergo intramolecular insertion into CH of the alkoxycarbonyl group giving β-lactones which under the conditions lose CO2 to afford alkenyl sulfides.