51527-45-8Relevant academic research and scientific papers
Novel method for the synthesis of β-lactams by the reaction of α-bromocarboxylic acids with imines mediated by triphenylphosphine
Kikuchi, Satoshi,Hashimoto, Yukihiko
, p. 453 - 457 (2006)
The useful and simple method for the formation of the β-lactams by the reaction between α-bromo carboxylic acids and imines is described. This reaction was effectively mediated by triphenylphosphine or polystyryl-diphenylphosphine to given the β-lactams i
One-pot synthesis of trans-β-lactams from ferrocenylketene generated by thermal Wolff rearrangement
Liu, Mingshun,Wang, Jian’an,Yuan, Xiaoxi,Jiang, Rong,Fu, Nanyan
supporting information, p. 2369 - 2377 (2017/12/12)
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 h
Pd-catalyzed carbonylation of diazo compounds at atmospheric pressure: A catalytic approach to ketenes
Zhang, Zhenhua,Liu, Yiyang,Ling, Lin,Li, Yuxue,Dong, Yian,Gong, Mingxing,Zhao, Xiaokun,Zhang, Yan,Wang, Jianbo
supporting information; experimental part, p. 4330 - 4341 (2011/06/21)
The carbonylation of carbenes through catalytic cycles is highly desirable due to the importance of ketene-mediated reactions in organic synthesis. In this investigation, a highly efficient and mild catalytic approach toward ketene intermediates has been developed based on Pd-catalyzed carbonylation of diazo compounds with CO. When α-diazocarbonyl compounds or N-tosylhydrazone salts are heated in the presence of a palladium catalyst under atmospheric pressure of CO, ketene intermediates are formed in situ, where they undergo further reactions with various nucleophiles such as alcohols, amines, or imines. The Pd-catalyzed tandem carbonylation-Staudinger cycloaddition gives β-lactam derivatives in good yields with excellent trans diastereoselectivity. The results from DFT calculation on the reaction mechanism suggest that Pd is involved in the [2 + 2] cycloaddition process and affects the diastereoselectivity of the β-lactam products by assisting isomerization of the addition intermediate. On the other hand, the acylketenes generated from the Pd-catalyzed carbonylation of α-diazoketones react with imines in a formal [4 + 2] cycloaddition manner to afford 1,3-dioxin-4-one derivatives. This straightforward carbonylation provides a new approach toward highly efficient catalytic generation of ketene species under mild conditions.
Copper-Catalyzed Reaction of Terminal Alkynes with Nitrones. Selective Synthesis of 1-Aza-1-buten-3-yne and 2-Azetidinone Derivatives
Miura, Masahiro,Enna, Masahiro,Okuro, Kazumi,Nomura, Masakatsu
, p. 4999 - 5004 (2007/10/03)
Reaction of arylacetylenes with C,N-diarylnitrones using a catalyst system of CuI-dppe (dppe = 1,2-bis(diphenylphosphino)ethane) in the presence of potassium carbonate in DMF predominantly affords the corresponding 1,2,4-triaryl-1-aza-1-buten-3-ynes in good yields.In contrast, the catalytic reaction using CuI in the presence of an excess amount of pyridine as the ligand gives 1,3,4-triaryl-2-azetidinones as the major products.The reaction with aliphatic terminal alkynes in place of arylacetylenes produces the latter products irrespective of the catalyst system used.Asymmetric induction is also observed in the reaction of phenylacetylene with α,N-diphenylnitrone to give 1,2,4-triphenyl-2-azetidinone in the presence of chiral bisoxazoline-type ligands.
β-LACTAM FORMATION VIA ENOLATE ADDITION: AN UNEXPECTED METHYLENATION REACTION
Manhas, Maghar S.,Chaudhary, Ashok G.,Raju, Vegesna, S.,Robb, Ernest W.,Bose, Ajay K.
, p. 635 - 638 (2007/10/02)
The condensation of ethyl phenylacetate or ethyl β-hydroxybutyrate with Schiff bases in presence of an excess of lithium diisopropylamide or lithium hexamethyldisilazide leads to unsaturated amides instead of the expected β-lactams.
