19340-68-2Relevant academic research and scientific papers
Asymmetric synthesis of β-lactam via palladium-catalyzed enantioselective intramolecular c(sp3)-h amidation
Tong, Hua-Rong,Zheng, Wenrui,Lv, Xiaoyan,He, Gang,Liu, Peng,Chen, Gong
, p. 114 - 120 (2019/12/24)
β-Lactams are important scaffolds in drug design and frequently used as reactive intermediates in organic synthesis. Catalytic reactions featuring intramolecular C-H amidation of alkyl carboxamide substrates could provide a straightforward disconnection strategy for β-lactam synthesis. Herein, we report a streamlined method for asymmetric synthesis of β-aryl β-lactams from propanoic acid and aryl iodides via Pd-catalyzed sequential C(sp3)-H functionalization. The lactam-forming reaction provides an example of PdII-catalyzed enantioselective intramolecular C(sp3)-H amidation reaction and proceeds up to 94% ee. The use of a 2-methoxy-5-chlorophenyl iodide oxidant is critical to control the competing reductive elimination pathways of the PdIV intermediate to achieve the desired chemoselectivity. Mechanistic studies suggest that both steric and electronic effects of the unconventional aryl iodide oxidant are responsible for controlling the competing C-N versus C-C reductive elimination pathways of the PdIV intermediate.
Copper-Catalyzed Oxidative Benzylic C(sp3)?H Cyclization for the Synthesis of β-Lactams
Nozawa-Kumada, Kanako,Saga, Satoshi,Matsuzawa, Yuta,Hayashi, Masahito,Shigeno, Masanori,Kondo, Yoshinori
supporting information, p. 4496 - 4499 (2020/04/10)
β-Lactams are important structural motifs because of their ubiquity in natural products and pharmaceuticals. We report herein a Cu-catalyzed intramolecular oxidative C(sp3)?H amidation for the synthesis of β-lactams using tBuOOtBu. This method
Synthesis of Exclusively 4-Substituted β-Lactams through the Kinugasa Reaction Utilizing Calcium Carbide
Hosseini, Abolfazl,Schreiner, Peter R.
supporting information, p. 3746 - 3749 (2019/05/24)
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.
Chemoselective synthesis of β-amino ester or β-lactam via sonochemical reformatsky reaction
Lee, Adam Shih-Yuan,Chang, Yu-Ting,Su, Feng-Yi
, p. 290 - 294 (2014/05/06)
A series of β-amino esters were synthesized by the reaction of N-tosyl aldimine or N-hydroxy aldimine with bromoacetate by sonochemical Reformatsky reaction. The β-N-hydroxyamino ester was obtained and the formed sensitive hydroxylamino functionality was
Synthesis of densely substituted trans-configured 4-acylated piperidine-2,4-diones as 3:1 Adducts of imines and ketenes
Cabrera, Jose,Hellmuth, Tina,Peters, Rene
scheme or table, p. 4326 - 4329 (2010/09/03)
An operationally simple method is described to form densely substituted diastereomerically pure trans-configured and potentially biologically interesting 5,6-dihydropyridone derivatives as 3:1 adducts of ketenes formed in situ from acyl bromides and aromatic imines.
A general and versatile synthesis of 3-phenylthio β-lactams as lead molecules for 3-methyl-2-azetidinones
Kanwar, Seema,Sharma
, p. 1121 - 1128 (2008/03/29)
(Chemical Equation Presented) Ketene-imine cycloaddition using phosphorus oxychloride and benzenesulfonyl chloride under the described reaction conditions yielded trans 3-phenylthio 2-azetidinones in good yields. Desulfurization using Raney nickel and alk
The synthesis of β-lactams via a one-pot Reformatsky reaction of imines promoted by Zn/Cp2TiCl2 (cat.)
Chen, Lei,Zhao, Gang,Ding, Yu
, p. 2611 - 2614 (2007/10/03)
In the presence of Zn/Cp2TiCl2 (cat.) α-bromoacetates, γ-bromocrotonates or α-bromomethylacrylates react with imines in one-pot to form β-lactams, 3-vinyl-β-lactams or α-methylene-γ-lactams, respectively, at room temperature without
Selective synthesis of β-amino esters and β-lactams by rhodium-catalyzed reformatsky-type reaction
Kanai, Kazuo,Wakabayashi, Hitoshi,Honda, Toshio
, p. 47 - 51 (2007/10/03)
β-Amino esters and β-lactams are synthesized selectively from aldimines and ethyl bromoacetate by applying a simply modified rhodium-catalyzed Reformatsky-type reaction.
Indium-mediated facile synthesis of 3-unsubstituted β-lactams
Banik, Bimal K.,Ghatak, Anjan,Becker, Frederick F.
, p. 2179 - 2181 (2007/10/03)
A simple synthesis of 3-unsubstituted β-lactams was achieved through indium-mediated reaction of imines with ethyl bromoacetate. An ultrasound-promoted synthesis of 3-unsubstituted β-lactam using ethyl bromoacetate, zinc and imines was reported. Imines obtained from arylalkylamines produced the β-lactams in higher yield than those obtained from aryl- or allylamines.
3-Methylidene-β-lactams as potential inhibitors of β-lactamases. Part 1: Synthesis of α-substituted derivatives from imines by Reformatzky reaction with chlorotrimethylsilane, silylation and Peterson olefination
Guertler,Ruf,Johner,Otto
, p. 811 - 815 (2007/10/03)
A new variation of the Reformatzky reaction with use of I2/zinc and chlorotrimethylsilane in THF and a shortened work-up is described allowing the synthesis of a wide variety of substituted β-lactams 3 in fairly good yield. These lactams are silylated according to the Peterson reaction yielding by reactions with appropriate carbonyl compounds E/Z-mixtures of the substituted 3-methylidene β-lactams 7, 8 and 10. The isomers are separated by CC and completely characterized by spectroscopic methods, mainly 1H NMR spectroscopy. Condensation of the 3-formyl methylidene derivative 10 with amines or malonate yields the conjugated products 11, and from the isopropylidene derivative 6 the pyridinium sulfonate 14 is prepared via 12 and 13. All methylidene β-lactams are prepared as model compounds for studying their activity against β-lactamases and for elucidating the mechanism of action.
