我们开发了一种使用带有磺酸部分的两亲性整体树脂作为阳离子交换功能(整体-SO 3 H)将羧酸与醇酯化的方法。Monolith-SO 3 H 在 60–80 °C 下,在甲苯中有效地催化芳香族和脂肪族羧酸与各种伯醇和仲醇(1.5–5.0 当量)的酯化反应,无需去除反应过程中产生的水。Monolith-SO 3的两亲性H 由于其吸水能力而促进脱水。该反应也适用于硫酯化,尽管需要在 120 °C 下加热,但仅使用 2.0 当量的硫醇在甲苯中即可以优异的收率获得相应的硫酯。此外,整体式-SO 3 H 可通过简单的过滤从反应混合物中分离出来,并在不降低催化活性的情况下重复使用至少五次。
Manganese-catalyzed homogeneous hydrogenation of ketones and conjugate reduction of α,β-unsaturated carboxylic acid derivatives: A chemoselective, robust, and phosphine-free in situ-protocol
作者:Thomas Vielhaber、Christoph Topf
DOI:10.1016/j.apcata.2021.118280
日期:2021.8
glove-box-free catalytic protocol for the manganese-catalyzed hydrogenation of ketones and conjugated CCbonds of esters and nitriles. The respective catalyst is readily assembled in situ from the privileged [Mn(CO)5Br] precursor and cheap 2-picolylamine. The catalytic transformations were performed in the presence of t-BuOK whereby the corresponding hydrogenation products were obtained in good to excellent yields
我们传达了一种用户友好且无需手套箱的催化协议,用于酮和酯和腈的共轭 C C键的锰催化氢化。相应的催化剂很容易由特权 [Mn(CO) 5 Br] 前体和廉价的 2-吡啶甲胺原位组装。催化转化在t- BuOK存在下进行,从而以良好至极好的收率获得相应的氢化产物。所描述的系统提供了对仲醇和饱和酯的快速和原子效率的访问,避免了使用氧敏感和昂贵的基于膦的配体。
Syntheses and reactivities of non-symmetrical “active ester” bi-dentate cross-linking reagents having a phthalimidoyl and acid chloride, 2-benzothiazole, or 1-benzotriazole group
active ester” bi-dentate cross-linking reagents having an acid chloride, 2-benzothiazole, or 1-benzotriazole group (i.e., 9, 15, and 16) on the basis of the reactivity study of the “active ester” model compounds, 11–14, toward the various nucleophiles and examined their reaction selectivity towards the same nucleophiles. Then, we applied for the modification of cholesterol at the more reactive site of
Broadly Applicable Ytterbium-Catalyzed Esterification, Hydrolysis, and Amidation of Imides
作者:Céline Guissart、Andre Barros、Luis Rosa Barata、Gwilherm Evano
DOI:10.1021/acs.orglett.8b01896
日期:2018.9.7
An efficient, broadlyapplicable, operationally simple, and divergent process for the transformation of imides into a range of carboxylic acid derivatives under mild conditions is reported. By simply using catalytic amounts of ytterbium(III) triflate as a Lewis acid promoter in the presence of alcohols, water, amines, or N,O-dimethylhydroxylamine, a broad range of imides is smoothly and readily converted
the operationally simple dehydrative condensation of carboxylic acids. This reagent comprises an ATD core and DMAP as the leaving group, which is liberated into the reaction system to accelerate acyltransfer reactions. Upon adding ATD-DMAP to a mixture of carboxylic acids and alcohols in the presence of an amine base, the corresponding esters were formed rapidly at room temperature. Moreover, dehydrative
开发了一种新的基于三嗪二酮的试剂 ( N , N'-二烷基)三嗪二酮-4-(二甲氨基)吡啶 (ATD-DMAP),用于操作简单的羧酸脱水缩合。该试剂包含一个ATD核和作为离去基团的DMAP,它被释放到反应体系中以加速酰基转移反应。在胺碱存在下将 ATD-DMAP 添加到羧酸和醇的混合物中,在室温下迅速形成相应的酯。此外,使用 ATD-DMAP 使羧酸和胺之间的脱水缩合以高产率进行。
Development of triazine-based esterifying reagents containing pyridines as a nucleophilic catalyst
作者:Kohei Yamada、Jie Liu、Munetaka Kunishima
DOI:10.1039/c8ob01660g
日期:——
as a nucleophilic catalyst. 1-(4,6-Dimethoxy-1,3,5-triazin-2-yl)-3,5-lutidinium chloride (DMT-3,5-LUT) was found to exhibit a superior reactivity for the dehydrating condensation reaction betweencarboxylicacids and alcohols. The reaction of DMT-3,5-LUT with carboxylicacids produces intermediacy of acyloxytriazines, which is known to exhibit moderate reactivity toward alcohols, with concomitant liberation