Chemoselective alkynylation of N-sulfonylamides versus amides and carbamates – Synthesis of tetrahydropyrazines
作者:Thomas Aubineau、Janine Cossy
DOI:10.1039/c3cc40529j
日期:——
The chemoselective alkynylation of N-sulfonylamides versus amides and carbamates using TMS-EBX as an alkynylatingagent leads to the formation of non-symmetrical tetrahydropyrazines from orthogonally protected diamines.
Ethynylbenziodoxolones (EBX) as Reagents for the Ethynylation of Stabilized Enolates
作者:Davinia Fernández González、Jonathan P. Brand、Régis Mondière、Jérôme Waser
DOI:10.1002/adsc.201300266
日期:2013.5.17
with ethynylbenziodoxolone (EBX) reagents. The structure and stability of this class of reagents is first described more in details. Differential scanning calorimetry (DSC) experiments showed a strong exothermic decomposition with EBXreagents, leading to guidelines for the safe use of these compounds. The extension of the method to aromatic alkynes and a broad range of benziodoxol(on)e reagents is then
在此,我们报告的环酮酯和酰胺的电炔基随着研究的深入ê thynyl b enziodo X olone(EBX)试剂。首先更详细地描述这类试剂的结构和稳定性。差示扫描量热法(DSC)实验表明,使用EBX试剂会发生强烈的放热分解,从而为安全使用这些化合物提供了指导。然后报道了将该方法扩展到芳族炔烃和广泛的苯并齐多酚(on)e试剂。根据我们使用Cinchona的初步结果基于相转移催化剂,可以实现环酮酯的对映选择性炔基化。由Maruoka和他的同事开发的由联萘胺衍生的铵催化剂提供了最高的不对称诱导率,对于茚满酮衍生的酮酯,ee高达79%。在整个工作过程中,仅在苯并恶唑酮试剂中观察到不对称诱导,证明了它们优于常规烷基炔诺酮盐。对导致更高的不对称诱导的因素的更深入的了解将在将来开发一种真正通用的和高度对映选择性的炔基化方法中非常有用。
NH<sub>2</sub>-Directed C–H Alkenylation of 2-Vinylanilines with Vinylbenziodoxolones
作者:Andreas Boelke、Lucien D. Caspers、Boris J. Nachtsheim
DOI:10.1021/acs.orglett.7b02630
日期:2017.10.6
directing-group-mediated C–H alkenylation with alkenyl-λ3-iodanes as electrophilic alkene-transfer reagents has been developed. The application of free aromatic amines as challenging but synthetically valuable directing groups in combination with an IrIII catalyst enabled the synthesis of highly desirable 1,3-dienes in excellent yields of up to 98% with high to perfect (Z,E) stereoselectivity. A broad substrate
The synthesis of a crystalline ethynyl-1,2-benziodoxol-3(1H)-one (EBX)–acetonitrile complex is described. EBX has been widely used as an active species for a variety of reactions; however, its high instability has so far prevented its isolation. The EBX–acetonitrile is self-assembled into a double-layered honeycomb structure through weak hypervalent iodine secondary interactions and hydrogen bonding
Metal-Free Three-Component Oxyalkynylation of Alkenes
作者:Yangshan Li、Ran Lu、Shutao Sun、Lei Liu
DOI:10.1021/acs.orglett.8b02954
日期:2018.11.2
An unprecedented (NH4)2S2O8 mediated metal-free three-componentalkene oxyalkynylation using H2O or alcohol as oxygenation agent is described. Mechanistic studies suggested that the reversed regioselectivity should be dictated by an alkene radical cation intermediate.
描述了前所未有的(NH 4)2 S 2 O 8介导的使用H 2 O或醇作为氧化剂的无金属三组分链烯氧基炔基化反应。机理研究表明,逆向的区域选择性应由烯烃自由基阳离子中间体决定。