51527-45-8Relevant articles and documents
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
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.
2-Azetidinones as inhibitors of cholesterol absorption
Burnett,Caplen,Davis Jr.,Burrier,Clader
, p. 1733 - 1736 (2007/10/02)
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