5449-36-5Relevant academic research and scientific papers
Synthesis of Amido Esters and Amido Phosphonates through Carbonylation of Diazo Compounds Followed by Nucleophilic Addition Reaction
Ramakrishna, Kankanala,Sivasankar, Chinnappan
, p. 4035 - 4043 (2017/07/28)
We report a method to produce amido esters and amido phosphonates. Octacarbonyldicobalt [Co2(CO)8] was found to be an efficient nongaseous CO source that could be used as a reagent for the carbonylation of diazo esters and diazo phosphonates under mild reaction conditions. A number of diazo esters and diazo phosphonates smoothly underwent the reaction with CO, which was generated from Co2(CO)8, to produce the corresponding ketenes. The subsequent reaction with an amine afforded the expected amido esters and phosphonates. By applying the developed protocol, we synthesized a number of amido esters and amido phosphonates. Characterization of these compounds was achieved by using standard spectroscopic and analytical techniques as well as crystal structure analysis for four of the products.
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.
The chemistry of 5-oxodihydroisoxazoles. XX: Photolysis of 2,4-diphenylisoxazol-5(2H)-one: Evidence for singlet and triplet pathways
Ang, Kiah H.,Prager, Rolf H.
, p. 483 - 489 (2007/10/03)
2,4-Diphenylisoxazol-5(2H)-one (2) has been photolysed in the presence of alcohols, amines and in inert solvents, and the products are shown to arise by two competitive singlet state photolytic processes. The minor pathway involves loss of carbon dioxide to give an imino carbene which is captured by nucleophiles: the major pathway involves isomerization to a ketene which is rapidly decarbonylated, and the resultant carbene captured by solvent. The presence of acetone or other triplet sensitizers induces a third competitive pathway involving triplet states.
Photochemical Formation and Some Chemical Properties of 2,6-Diazabicyclohexane-3,5-diones from Pyrimidinium-4-olates. A New Approach to Novel Bis(β-lactans)
Gotthardt, Hans,Schenk, Karl-Heinz
, p. 687 - 688 (2007/10/02)
The pyrimidinium-4-olates of type (1) or (3) are photochemically isomerized into the novel bis(β-lactams) (2) or (4), respectively, and the bis(β-lactam) (2a) could be further converted into two monocyclic β-lactams.
