29689-63-2Relevant articles and documents
Carbene radicals in cobalt(II)-porphyrin-catalysed carbene carbonylation reactions; A catalytic approach to ketenes
Paul, Nanda D.,Chirila, Andrei,Lu, Hongjian,Zhang, X. Peter,Debruin, Bas
supporting information, p. 12953 - 12958 (2013/10/01)
One-pot radicals: Cobalt(III)-carbene radicals, generated by metallo-radical activation of diazo compounds and N-tosylhydrazone sodium salts with cobalt(II) complexes of porphyrins, readily undergo radical addition to carbon monoxide, allowing the catalytic production of ketenes. These ketenes subsequently react with various amines, alcohols and imines in one-pot tandem transformations to produce differently substituted amides, esters and β-lactams in good isolated yields. Copyright
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.
3-(1,3-dithiol-2-ylidene)-2,4-dioxopyrrolidines, -piperidines, and -hexahydroazepines and use thereof against hepatic diseases
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, (2008/06/13)
Novel thioketene derivatives of the formula: STR1 wherein R1 is hydrogen atom, an alkyl group, a lower alkenyl group, a phenyl group or a group of the formula: --B--Y; Y is a nitrogen-containing monocyclic heterocyclic group or a substituted or unsubstituted phenyl group; B is a straight or branched lower alkylene group; R2 and R3 are both a lower alkyl group or are combined together to form a group of the formula: --CH2 CH2 -- or --CH=CH--; R4 is hydrogen atom, a lower alkyl group or a (lower alkoxy)carbonyl group; A is a group of the formula: --(CH2)n -- or --CH(COOR5)--; n is an integer of 0, 1 or 2 and R5 is a lower alkyl group, are disclosed. The compound (I) is useful as an agent for treating and protecting various liver diseases.
