Thermodynamic, spectroscopic, and density functional theory studies of allyl aryl and prop-1-enyl aryl ethers. Part 1. Thermodynamic data of isomerization
Specific <i>Z</i>-Selectivity in the Oxidative Isomerization of Allyl Ethers to Generate Geometrically Defined <i>Z</i>-Enol Ethers Using a Cobalt(II)(salen) Complex Catalyst
作者:Guanxin Huang、Miaolin Ke、Yuan Tao、Fener Chen
DOI:10.1021/acs.joc.0c00004
日期:2020.4.17
synthesis of the geometrically less stable Z-enol ethers is challenging. An efficient Z-selective oxidative isomerization process of allyl ethers catalyzed by a cobalt(II) (salen) complex using N-fluoro-2,4,6-trimethylpyridinium trifluoromethanesulfonate (Me3NFPY•OTf) as an oxidant has been developed. Thermodynamically less stable Z-enol ethers were prepared in excellent yields with high geometric control.
demonstrate a dual organophotoredox/copper catalytic strategy toward challenging decarboxylative olefination processes proceeding in high yields and selectivities. This operationally simple method uses photoactive organic molecules and Cu(II)-complexes as catalysts to provide rapid access to a wide variety of olefins from inexpensive synthetic and biomass-derived carboxylic acids under mild light-mediated conditions
and convenient ruthenium(II) complex for the catalyticisomerization of O-allylethers, leading to thermodynamic-unfavored Z-product under mild conditions. The model substrate of allyl phenyl ether can be simply scaled up to 20 mmol to produce Z-product with TON of 2453 and TOF of 13,430 h−1 at 40–60 °C. The system of Ru(II)/Lewis Acidcatalysts was suitable for various substituted O-allylethers and other
在催化双键迁移反应中,通常以E-构型烯烃为主要产物,因为E-构型在热力学上是有利的。然而,由于结构-活性关系,有时在药物化学中需要Z-构型产物。在本文中,我们证明了一种新的策略,即路易斯酸促进了广泛使用且方便的钌(II)络合物用于O-烯丙基醚的催化异构化,导致在温和条件下产生热力学不利的Z产物。烯丙基苯基醚的模型底物可以简单地按比例放大至20 mmol以生产TON为2453,TOF为13,430 h -1的Z产物在40–60°C下。Ru(II)/路易斯酸催化剂体系适用于各种取代的O-烯丙基醚和其他类型的底物。通过包括动力学研究,配体抑制作用和分子光谱在内的机理研究,通过添加路易斯酸使PPh 3配体解离,以及由嵌合助剂形成五元Ru络合物均被认为是提高反应性和稳定性的必要步骤。通过金属氢化物加成消除机理控制催化双键迁移反应的立体选择性。这一新策略可能为生产用于药物化学的杂环化合物中热力学不利的产品提供新的机会。
The development of strong covalent interactions in inner sphere electron transfer reactions between cation radicals and neutral molecules
作者:Nathan L. Bauld、J. Todd Aplin、Wang Yueh、Angie Loving、Stephanie Endo
DOI:10.1039/a708901e
日期:——
The cationradicalDiels–Alderreactions of a series of meta and para substituted aryl cis-prop-1-enyl ethers with 2,3-dimethylbuta-1,3-diene catalyzed by tris(4-bromophenyl)aminium hexachloroantimonate have been studied mechanistically. The reactions are found to occur primarily via an indirect route involving cationradical cyclobutanation followed by cationradical vinylcyclobutane rearrangement