on the azetidin-2-one ring formation. A 1H NMR investigation.
摘要:
Azetidin-2-ones were prepared by addition of phenylacetic acid chloride to substituted benzal-anilines in DMF. The effect of temperature and substituents at the benzal-anilines on the reaction mechanism was investigated, carrying out the reaction in DMF d7 in an NMR probe of a Bruker 400-MHz spectrometer, at 25 and 60-degrees-C. Proton signals, arising from two kinds of intermediates, a 2-phenyl-N-(alpha-chlorobenzyl)-acetanilide (6) and a nitrogen-charged adduct (7), suggest that two competitive mechanisms play a role in the formation of trans and cis azetidin-2-ones.
CuFe<sub>2</sub>O<sub>4</sub> nanoparticles catalyze the reaction of alkynes and nitrones for the synthesis of 2-azetidinones
作者:Maaroof Zarei
DOI:10.1039/d0nj02660c
日期:——
CuFe2O4 nanoparticles acted as a highly efficient heterogeneous catalyst in the reaction of alkynes and nitrones (Kinugasa reaction) for the synthesis of various 2-azetidinones. In all cases, the reactions proceeded conveniently under mild conditions with good-to-excellent yields and with a wide range of functional-group tolerance. The catalyst could be separated readily using an external magnet.
CuFe 2 O 4纳米颗粒在炔烃和硝酮的反应(Kinugasa反应)中用于合成各种2-氮杂环丁酮,是一种高效的多相催化剂。在所有情况下,反应均在温和的条件下方便地进行,具有良好至优异的产率和宽泛的官能团耐受性。使用外部磁体可以容易地分离催化剂。
Synthesis of Exclusively 4-Substituted β-Lactams through the Kinugasa Reaction Utilizing Calcium Carbide
作者:Abolfazl Hosseini、Peter R. Schreiner
DOI:10.1021/acs.orglett.9b01192
日期:2019.5.17
A new Kinugasa reaction protocol has been elaborated for the one-pot synthesis of 4-substituted β-lactams utilizing calcium carbide and nitrone derivatives. Calcium carbide is thereby activated by TBAF·3H2O in the presence of CuCl/NMI. The ease of synthesis and use of inexpensive chemicals provides rapid access of practical quantities of β-lactams exclusively substituted at position 4.
Carbocation catalyzed carboxylic acid activation in Staudinger reaction for stereoselective synthesis of β-lactams
作者:Ankita Rai、Puneet K. Singh、Prashant Shukla、Vijai K. Rai
DOI:10.1016/j.tetlet.2016.10.012
日期:2016.11
stereoselective β-lactams has been disclosed via cyclopropenium-ion-catalyzed reaction of substituted acetic acids with aldimines under mild conditions. Products are formed in high yields (86–95%) and good diastereoselectivity within 3–4 h. The new reaction is focused on the exploration of the scope of cyclopropenium-ion catalysis and introduction of a catalytic version of one-step Staudinger reaction for β-lactam
One-pot synthesis of <i>trans</i>-<font>β</font>-lactams from ferrocenylketene generated by thermal Wolff rearrangement
作者:Mingshun Liu、Jian’an Wang、Xiaoxi Yuan、Rong Jiang、Nanyan Fu
DOI:10.1080/00397911.2017.1378358
日期:2017.12.17
ABSTRACT A series of β-lactams containing the ferrocene moiety were synthesized through the Staudinger reaction between ferrocenylketene generated by the thermal Wolff rearrangement of the corresponding diazo ketone and various imines. The stereochemical outcome has been investigated and the trans-products were isolated as the main products, opposite to the reported results by Bonini and coworkers
摘要 通过相应重氮酮的热沃尔夫重排产生的二茂铁基烯酮与各种亚胺之间的施陶丁格反应合成了一系列含有二茂铁部分的β-内酰胺。立体化学结果已被研究,反式产物作为主要产物被分离出来,这与 Bonini 和同事报告的结果相反。(±)-trans-1,4-diphenyl-3-ferrocenylazetidin-2-one (3c) 的绝对构型通过 X 射线分析确定。从反应机理的角度讨论立体选择性。图形概要
Ring splitting of azetidin-2-ones via radical anions
作者:Raúl Pérez-Ruiz、Jose A. Sáez、Luis R. Domingo、M. Consuelo Jiménez、Miguel A. Miranda
DOI:10.1039/c2ob26528a
日期:——
The radicalanions of azetidin-2-ones, generated by UV-irradiation in the presence of triethylamine, undergo ring-splitting via N–C4 or C3–C4 bond breaking, leading to open-chain amides. This reactivity diverges from that found for the neutral excited states, which is characterised by α-cleavage. The preference for β-cleavage is supported by DFT theoretical calculations on the energy barriers associated