洞察安全,简单且廉价的磷酸(H 3 PO 4描述了醇用酸酐的)催化的酰化。与传统上提出的单酰化混合酸酐不同,提出了相应的原位生成的二酰化混合酸酐作为活性物质。特别地,二酰基化的混合酸酐充当有效的催化酰基转移试剂,而不是充当简单活化酸酐的布朗斯台德酸催化剂。值得注意的是,实现了高效磷酸(1-3 mol%)催化的醇与酸酐的酰化作用,并证明了23 g规模的酯的合成。另外,磷酸催化剂对于从羧酸,醇和酸酐的合成有用的酯化是有效的。此外,关于手性1的最新发展,1'-联-2-萘酚(BINOL)衍生的磷酸二酯催化剂通过酰化作用对醇的不对称动力学拆分,研究了一些磷酸二酯。结果,31 P NMR研究和动力学研究不仅大力支持了其他研究人员先前提出的酸碱协同机理,而且也大力支持了我们目前提出的混合酸酐机理。
作者:Lijun Lu、Renyi Shi、Luyao Liu、Jingwen Yan、Fangling Lu、Aiwen Lei
DOI:10.1002/chem.201602791
日期:2016.10.4
compounds is an attractive prospect in organic synthesis. In particular, the combination of C(sp3)−H activation and oxidative carbonylation involving alkanes and CO gas is a promising and efficient method to synthesize carbonyl derivatives. However, due to the high C−H bond dissociation energy and low polarity of unactivated alkanes, the carbonylation of unactivated C(sp3)−H bonds still remains a great challenge
A Facile, Catalytic and Environmentally Benign Method for Esterification of Carboxylic Acids and Transesterification of Carboxylic Esters with Nearly Equimolar Amounts of Alcohols
A practical and green chemical process for the esterification of carboxylic acids with alcohols and transesterification of carboxylic esters in good to excellent yields by using K5CoW12O14·3H2O (0.1 mol%) as catalyst is reported. The catalyst exhibited remarkable reusable activity.
Diphenylammonium triflate (DPAT): efficient catalyst for esterification of carboxylic acids and for transesterification of carboxylic esters with nearly equimolar amounts of alcohols
Diphenylammonium triflate (DPAT) efficiently catalyzed esterification betweenequimolaramounts of carboxylicacids and alcohols in good to excellent yields under mild reaction conditions. Transesterification of carboxylicesters with a slight excess of alcohols also proceeded using DPAT as catalyst with TMSCl as a co-catalyst.
We have developed an efficient method for the esterification or thioesterification of equimolar amounts of carboxylic acids and alcohols or thiols using a novel reagent, p-toluenesulfonylchloride (TsCl) together with N-methylimidazole. The present method is simple, mild, and reactive, uses readily available and economical reagents. The choice of amine is critical for the present method. The amine
我们已经开发了一种有效的方法,使用新型试剂对甲苯磺酰氯(TsCl)和N-甲基咪唑对等摩尔量的羧酸,醇或硫醇进行酯化或硫酯化。本方法简单,温和,反应活性强,使用容易获得且经济的试剂。胺的选择对于本方法是至关重要的。胺,N-甲基咪唑具有两个作用:(i)作为HCl清除剂,用于初始平滑生成羧酸和TsCl之间的混合酸酐,以及(ii)由混合酸酐连续形成高反应性的铵中间体。该方法可应用于各种类型的羧酸,醇和硫醇:b)两个N-Cbz氨基酸被平滑酯化而没有外消旋;c)成功制备了不稳定的1β-甲基卡巴培南关键中间体和拟除虫菊酯杀虫剂普乐菌素。还进行了羧酸与伯胺或仲胺之间的相关酰胺形成。拟议的反应机理涉及一种生产反应性酰基lam中间体的新方法。仔细的1 H NMR监测研究合理地支持了这些中间体的生产。
Me2NSO2Cl and N,N-dimethylamines; a novel and efficient agent for esterification, amidation between carboxylic acids, and equimolar amounts of alcohols and amines
作者:Kazunori Wakasugi、Atsushi Nakamura、Yoo Tanabe
DOI:10.1016/s0040-4039(01)01444-7
日期:2001.10
amides were prepared in good to excellent yields between carboxylic acids and equimolar amounts of alcohols or amines under very mild conditions using dimethylsulfamoyl chloride (Me2NSO2Cl) combined with N,N-dimethylamines. The choice of the sulfamoylchloride and the amine is crucial for the reactions.