Effect of polymer attachment on the equilibrium acidity of an organotransition metal hydride and an organic carboxylic acid. Synthesis and properties of a polymer-supported metal anion
Facile one-pot syntheses of amidines and enamines were achieved by trapping carbocation intermediates that were formed by Beckmann rearrangement of oximes with amines and carbon nucleophiles, respectively, under mild conditions.
Iminocarbocation intermediates were in situ-generated by treating various oximes with trifluoromethanesulfonic anhydride (Tf2O) in the presence of triethylamine in toluene and nucleophilic trapping with amines or sodium enolates under mild conditions afforded the corresponding amidines and enamines. Some of the thus-obtained enamines were converted to 2-substituted 4-oxo-3-quinolinecarboxylic acid derivatives by subsequent intramolecular Friedel–Crafts acylation.
Preparation and Reactivities of (η<sup>3</sup>-1- and 2-Trimethylsiloxyallyl)Fe(CO)<sub>2</sub>NO Complexes. Intermediates Functioning as Equivalents of β- and α-Acyl Carbocations and Acyl Carbanions
作者:Keiji Itoh、Saburo Nakanishi、Yoshio Otsuji
DOI:10.1246/bcsj.64.2965
日期:1991.10
(η3-1- and 2-Trimethylsiloxyallyl)Fe(CO)2NO complexes were prepared by the reaction of the corresponding siloxyallylic halides with Bu4N[Fe(CO)3NO]. These complexes reacted with both of carbon nucleophiles and carbon electrophiles preferentially at the less hindered sites of the allylic ligands. In these reactions, (η3-1-trimethylsiloxyallyl)Fe(CO)2NO complexes served as synthetically equivalent synthons
Polyene cyclizations using mercury (II) triflate-N,N-dimethylaniline complex - participation by internal nucleophiles
作者:Aravamudan S. Gopalan、Robert Prieto、Britta Mueller、David Peters
DOI:10.1016/s0040-4039(00)91704-0
日期:1992.3
The cyclization of a number of functionalized polyenes with mercuric triflate - N,N-dimethylaniline complex (Nishizawa's reagent) to give bicyclic or tricyclic products has been studied. Suitably positioned internal nucleophiles, such as carbonyl, hydroxy and β-ketoester groups were found to participate to varying extent, in the termination of these cyclizations.
Photochemical synthesis of a 4,5-dihydrofuroazetidinone, a novel β-lactam system
作者:Donato Donati、Stefania Fusi、Fabio Ponticelli
DOI:10.1016/j.tetlet.2003.10.079
日期:2003.12
2,4-Dimethyl-3-phenylisoxazole anhydrobases were easily prepared from the corresponding 5-chloroisoxazolium trifluoromethanesulfonate and carbon anions of 1,3-dioxo compounds in the presence of triethylamine. Photorearrangement of 2-(2,4-dimethyl-3-phenyl-2H-isoxazol-5-ylidene)malonic acid diethyl ester gave a 4,5-dihydrofuroazetidinone in good yield.