A Cross-Coupling Approach to Amide Bond Formation from Esters
作者:Taoufik Ben Halima、Jaya Kishore Vandavasi、Mohanad Shkoor、Stephen G. Newman
DOI:10.1021/acscatal.7b00245
日期:2017.3.3
A palladium-catalyzed cross-coupling between aryl esters and anilines is reported, enabling access to diverse amides. The reaction takes place via activation of the C–O bond by oxidative addition with a Pd–NHC complex, which enables the use of relatively non-nucleophilic anilines that otherwise require stoichiometric activation with strong bases in order to react. High yields of aromatic, aliphatic
Competing S N2 and carbonyl addition pathways for solvolyses of benzoyl chloride in aqueous media
作者:T. William Bentley、Gillian E. Carter、H. Carl Harris
DOI:10.1039/p29850000983
日期:——
highly aqueous media is described. Rate and product data are reported for solvolyses of benzoyl chloride at 25 °C in water and in binary aqueous mixtures with acetone, ethanol, methanol, trifluoroethanol, and hexafluoropropan -2-ol. Comparison of these kinetic data with rate data for the SN1 model, 1 -adamantyl chloride, reveals sensitivity to solvent nucleophilicity even for highly aqueous media.
描述了一种便利的电导方法的进一步发展,该方法用于研究高水介质中相对较快的溶剂分解反应的速率。报告了速率和产物数据,用于分析苯甲酰氯在25°C水中和与丙酮,乙醇,甲醇,三氟乙醇和六氟丙烷-2-醇的二元含水混合物中的溶剂分解。这些动力学数据与S N的速率数据的比较1个模型1-金刚烷酰氯即使对于水性介质也显示出对溶剂亲核性的敏感性。与其他亲核溶剂辅助方法相反,溶剂效应不是通过一个线性自由能关系令人满意地关联的。气相热化学数据表明,在苯甲酰氯中直接进行C–Cl键的杂合裂解是可行的。观察到在50%w / w丙酮-水中水解和氨解的速率-产物相关性,但要考虑到添加的邻硝基苯胺对介质的影响。这些结果符合S N 2机制,而不符合S N1和/或先前讨论的离子对机理。在较少的水性介质中占主导地位的另一种途径对溶剂电离能力的变化不那么敏感,这与较早提出的羰基加成-消除机理的提议是一致的。
Unprecedented Iron-Catalyzed Ester Hydrogenation. Mild, Selective, and Efficient Hydrogenation of Trifluoroacetic Esters to Alcohols Catalyzed by an Iron Pincer Complex
作者:Thomas Zell、Yehoshoa Ben-David、David Milstein
DOI:10.1002/anie.201311221
日期:2014.4.25
synthetically important, environmentally benign hydrogenation of esters to alcohols has been accomplished in recent years only with precious‐metal‐based catalysts. Here we present the first iron‐catalyzedhydrogenation of esters to the corresponding alcohols, proceeding selectively and efficiently in the presence of an ironpincer catalyst under remarkably mild conditions.
framework of ate complex mechanism, suggesting formation of pentacoordinated titanium ate species as a prerequisite of high enantiocontrol. Asymmetric Kulinkovich cyclopropanation of carboxylic esters with prochiral alkenes is reported. The process is mediated by titanium(IV) (4R,5R)-TADDOLate complexes and affords correspondingly (Z)- or (E)-cyclopropanols with up to 84–87% ee in the event of intra- or
Tropolonate Salts as Acyl-Transfer Catalysts under Thermal and Photochemical Conditions: Reaction Scope and Mechanistic Insights
作者:Demelza J. M. Lyons、Claire Empel、Domenic P. Pace、An H. Dinh、Binh Khanh Mai、Rene M. Koenigs、Thanh Vinh Nguyen
DOI:10.1021/acscatal.0c03702
日期:2020.11.6
strong nucleophilicity and photochemical activity, can promote the coupling reaction between alcohols and carboxylic acid anhydrides or chlorides to give products under thermal or blue light photochemical conditions. Kinetic studies and density functional theory calculations suggest interesting mechanistic insights for reactions promoted by this acyl-transfer catalytic system.