Cobalt-Catalyzed Acceptorless Dehydrogenative Coupling of Primary Alcohols to Esters
作者:Keshav Paudel、Bedraj Pandey、Shi Xu、Daniela K. Taylor、David L. Tyer、Claudia Lopez Torres、Sky Gallagher、Lin Kong、Keying Ding
DOI:10.1021/acs.orglett.8b01775
日期:2018.8.3
A novel catalytic system with a tripodal cobalt complex is developed for efficiently converting primaryalcohols to esters. KOtBu is found essential to the transformation. A preliminary mechanistic study suggests a plausible reaction route that involves an initial Co-catalyzed dehydrogenation of alcohol to aldehyde, followed by a Tishchenko-type pathway to ester mediated by KOtBu.
为了有效地将伯醇转化为酯,开发了具有三脚架钴络合物的新型催化体系。KO t Bu被发现对转型至关重要。初步的机理研究表明,可能的反应路线包括最初的共催化将醇脱氢成醛,然后由Tishchenko型途径由KO t Bu介导生成酯。
Aldehyde effect and ligand discovery in Ru-catalyzed dehydrogenative cross-coupling of alcohols to esters
作者:Xiaolin Jiang、Jiahui Zhang、Dongmei Zhao、Yuehui Li
DOI:10.1039/c8cc10315a
日期:——
ligands for dehydrogenation of alcohols. Accordingly, hybrid multi-dentate ligands were discovered based on an oxygen-transfer alkylation of PNP ligands by aldehydes. The relevant Ru-PNN(PO) system provided the desired unsymmetrical esters in good yields via acceptorless dehydrogenation of alcohols. Hydrogen bonding interactions between the phosphine oxide moieties and alcohol substrates likely assisted
Rhodium-Catalyzed Synthesis of Imines and Esters from Benzyl Alcohols and Nitroarenes: Change in Catalyst Reactivity Depending on the Presence or Absence of the Phosphine Ligand
作者:Taemoon Song、Ji Eun Park、Young Keun Chung
DOI:10.1021/acs.joc.8b00197
日期:2018.4.6
catalyzes the reductive N-alkylation of aryl nitro compounds with alcohols by a borrowing-hydrogen strategy to afford the corresponding imine products in good to excellent yields. In the absence of xantphos, the [Rh(COD)Cl]2/Cs2CO3 catalytic system behaves as an effective catalyst for the dehydrogenative coupling of alcohols to esters, with nitrobenzene as a hydrogen acceptor. The reactivity of the
[Rh(COD)Cl] 2 / xantphos / Cs 2 CO 3系统通过借位氢策略有效催化芳基硝基化合物与醇的还原性N-烷基化,从而以良好或优异的收率提供相应的亚胺产品。在不存在黄药的情况下,[Rh(COD)Cl] 2 / Cs 2 CO 3催化体系可作为醇与酯脱氢偶联的有效催化剂,硝基苯为氢受体。铑催化体系的反应性可以很容易地控制以选择性地提供亚胺或酯。
Formamides as Lewis Base Catalysts in S<sub>N</sub>Reactions-Efficient Transformation of Alcohols into Chlorides, Amines, and Ethers
作者:Peter H. Huy、Sebastian Motsch、Sarah M. Kappler
DOI:10.1002/anie.201604921
日期:2016.8.16
and waste‐balance (E‐factor down to 2). Chiral substrates are converted with excellent levels of stereochemical inversion (99 %→≥95 % ee). In a practical one‐pot procedure, the primary formed chlorides can be further transformed into amines, azides, ethers, sulfides, and nitriles. The value of the method was demonstrated in straightforward syntheses of the drugs rac‐Clopidogrel and S‐Fendiline.
Easy access to benzylic esters directly from alkyl benzenes under metal-free conditions
作者:Ganesh Majji、Srimanta Guin、Anupal Gogoi、Saroj Kumar Rout、Bhisma K. Patel
DOI:10.1039/c3cc40832a
日期:——
An efficient metal free protocol has been developed for the synthesis of benzylic esters via a cross dehydrogenative coupling (CDC) involving alkylbenzene(s) as a self- or as a cross-coupling partner(s) via the intermediacy of Ar–COOH and the benzylic carbocation obtained from the other half of the alkylbenzene; both symmetrical as well as unsymmetrical esters can be prepared using Bu4NI and TBHP.