An efficient and convenient synthesis of 4-polyfluoroalkylated pyrrole-3-carboxylates through 1,3-dipolar cycloaddition reaction of polyfluoro-2-alkynoic acid esters with munchnones
1,3-Dipolarcycloaddition between polyfluoro-2-alkynoicacidesters and 1,3-oxazolium 5-olates (munchnones) readily proceeds in a regiospecific manner under very mild reaction conditions, followed by simultaneous decarboxylation to afford 4-(polyfluoroalkyl)pyrrole-3-carboxylate derivatives in good yield.
Catalytic Multicomponent Reactions for the Synthesis of <i>N</i>-Aryl Trisubstituted Pyrroles
作者:Chris V. Galliford、Karl A. Scheidt
DOI:10.1021/jo0624086
日期:2007.3.1
Dirhodium(II) salts efficiently catalyze the three-component assembly reaction of an imine, diazoacetonitrile (DAN), and an activated alkynyl coupling partner to form substituted 1,2-diarylpyrroles in moderate to good yields. The transition-metal-catalyzed decomposition of the diazocompound in the presence of the imine presumably generates a transient azomethine ylide that undergoes cycloaddition
The reaction of lithio α-chloromethyl phenyl sulfone with imines gave aziridines in good yields. The resulting aziridines were alkylated and underwent the 1,3-dipolar cycloaddition with dimethylacetylene dicarboxylate to give pyrroles in excellent yields.
The first example of the generation of azomethine ylides from a fluorocarbene: 1,3-cyclization and 1,3-dipolar cycloaddition
作者:Alexander S. Konev、Mikhail S. Novikov、Alexander F. Khlebnikov
DOI:10.1016/j.tetlet.2005.09.165
日期:2005.11
or dimethyl acetylenedicarboxylate, the products of dehydrofluorination of the primary adducts of the 1,3-dipolarcycloaddition of fluoro-substituted azomethine ylides to multiple bonds of dipolarophiles were obtained. In the case of the reaction of N-alkylimines of benzaldehyde the cycloaddition of ylides to dimethyl maleate completely suppressed the cyclization to aziridines.
Monofluoro-substituted azomethine ylides in fluorocarbene reactions with imines. Synthesis and transformations of monofluoroaziridines
作者:A. S. Konev、M. S. Novikov、A. F. Khlebnikov
DOI:10.1134/s1070428007020224
日期:2007.2
N-Arylmethylene and N-benzhydrylideneamines react with fluorocarbene yielding fluoro-substituted azomethine ylides that undergo 1,3-pi-cyclization into aziridines. Generation of fluoroylides in the presence of dipolarophiles (dimethyl maleate or dirnethyl acetylenedicarboxylate) led to the reaction of 1,3-dipolar cycloaddition resulting in substituted 2-pyrrolines or pyrroles. 2-Fluoroaziridines, products of N-alkyl-N-benzhydrylideneamines 1,3-pi-cyclization, in the presence of acid catalysts suffer isomerization into alpha-fluoroimines and 1,3-disubstituted indoles.