Photoinduced Alcoholysis of α,α,α-Tribromoacetophenone to Benzoylformate
作者:Yasuji Izawa、Katsuhiro Ishiguro、Hideo Tomioka
DOI:10.1246/bcsj.56.1490
日期:1983.5
Irradiation of p-substituted α,α,α-tribromoacetophenones (1) in O2-saturated alcohols (MeOH, prim. and sec. alcohols) afforded a new alcoholysis product, benzoylformate (2), in good yield (75–85%) along with benzoate and radical (reduction) products. Sensitization experiments showed that 2 was derived from the triplet excited 1. Formation of 2 as well as the decomposition rate of 1 were greatly accelerated
A Phosphetane Catalyzes Deoxygenative Condensation of α-Keto Esters and Carboxylic Acids via P<sup>III</sup>/P<sup>V</sup>═O Redox Cycling
作者:Wei Zhao、Patrick K. Yan、Alexander T. Radosevich
DOI:10.1021/ja511889y
日期:2015.1.21
A small-ring phosphacycle is found to catalyze the deoxygenative condensation of α-keto esters and carboxylic acids. The reaction provides a chemoselective catalytic synthesis of α-acyloxy ester products with good functional group compatibility. Based on both stoichiometric and catalytic mechanistic experiments, the reaction is proposed to proceed via catalytic P(III)/P(V)═O cycling. The importance
catalyzed controlled oxidation of terminal CC alkynes to α-keto esters and quinoxalines via formation of phenylglyoxals as stable intermediates, under mild conditions by using molecular O2 as a sustainable oxidant. The current copper catalysed photoredox method is simple, highly functional group compatible with a broad range of electron rich and electron poor aromatic alkynes as well as aliphatic alcohols
在此,我们报道了一种在温和条件下使用分子 O 2通过形成苯基乙二醛作为稳定的中间体,在可见光诱导的铜催化下,末端 C C 炔烃可控氧化为 α-酮酯和喹喔啉的方法。作为一种可持续的氧化剂。目前的铜催化光氧化还原方法简单、官能团高,与广泛的富电子和贫电子芳烃以及脂肪醇(1°、2°和3°醇)相容,为制备α-酮酯(43 个例子)、喹喔啉和萘醌的产率高于文献报道的热工艺。此外,该产品的合成效用已在两种生物活性分子的合成中得到证明,即大肠杆菌DHPS 抑制剂和 CFTR 活化剂,使用当前的光氧化还原过程。此外,我们将该方法应用于杂环化合物(喹喔啉,一种 FLT3 抑制剂)的一锅合成,方法是用邻苯二胺。也可以分离中间体苯乙二醛并进一步与内部炔烃反应以形成萘醌。这个过程可以很容易地放大到克级。
Nucleophilic Migratory Cyclopropenation of Activated Alkynes: A Nonmetal Approach to Unbiased Cyclopropenes
作者:Pengwei Tan、Haoran Wang、Sunewang R. Wang
DOI:10.1021/acs.orglett.1c00498
日期:2021.4.2
An unprecedented reductive [2 + 1] annulation of α-keto esters with alkynones mediated by P(NMe2)3 is described. Although this nonmetal cyclopropenation is a nucleophilic process, attributed to the ester migration via a formal [2 + 2] cycloaddition reaction of Kukhtin–Ramirez adducts and alkynones followed by a fragmentation, cyclopropenes with an unbiased alkene scaffold are formed in good to excellent
3-hydroxyoxindoles through tandem photoredox and chiral phosphoric acid catalysis is developed. The reaction involves an enantioselective photochemical radical–radicalcross-coupling process. The chiral phosphoric acid is discovered to play crucial roles by decreasing the reductive potentials of α-ketoesters and stereocontrolling the downstream asymmetricradical–radicalcross-coupling via the formation