An operationally simple, practical, and economical protocol for iron(III) chloride catalyzed Paal-Knorr pyrrole synthesis in water in good to excellent yields has been developed. Several N-substituted pyrroles are readily prepared from the reaction of 2,5-dimethoxytetrahydrofuran and aryl/alkyl, sulfonyl and acyl amines under very mild reaction conditions
Primary Sulfonamide Functionalization via Sulfonyl Pyrroles: Seeing the N−Ts Bond in a Different Light
作者:Tomoya Ozaki、Hideki Yorimitsu、Gregory J. P. Perry
DOI:10.1002/chem.202102748
日期:2021.11.5
Sulfonamides are prevalent in drug molecules, however, methods for functionalizingsulfonamidesvia S−N bond cleavage are scarce. Based on a re-evaluation of N−Ts deprotection, we developed sulfonylpyrroles as linchpins for sulfonamidefunctionalization. Sulfonylpyrroles engage in various transformations that can proceed through chemical, electrochemical or photochemical pathways.
N-acylpyrroles were synthesized via olefin ring-closingmetathesis of diallylamines and in situ oxidative aromatization in the presence of the ruthenium Grubbs catalyst and a suitable copper catalyst. In the presence of Cu(OTf)2 and CuBr2, the reaction afforded N-sulfonyl- and N-acylpyrroles, respectively, in one pot. Under an oxygen atmosphere, the reaction went smoothly without the need of hydroperoxide
Cross Metathesis of N-Allylamines and α,β-Unsaturated Carbonyl Compounds: A One-Pot Synthesis of Substituted Pyrroles
作者:Karol Grela、Syed Shafi、Mariusz Kędziorek
DOI:10.1055/s-0030-1259083
日期:2011.1
A tandem reaction involving cross metathesis followed by concomitant cyclisation has been developed for the synthesis of substituted pyrroles. Various protected electron-deficient N-allylamines reacted with α,β-unsaturated carbonyl compounds in the presence of Lewis acids under the cross metathesis conditions using selected Ru olefin metathesis catalysts in order to form pyrroles.
Triflic acid controlled successive annelation of aromatic sulfonamides: an efficient one-pot synthesis of N-sulfonyl pyrroles, indoles and carbazoles
作者:Mohammed Abid、Liliana Teixeira、Béla Török
DOI:10.1016/j.tetlet.2007.04.021
日期:2007.6
A novel one-pot synthesis of N-substituted heterocycles via successive cyclization/annelation starting from primary sulfonamides is described. This process leads directly to N-sulfonyl pyrroles, indoles and carbazoles. The selection of appropriate reactant/triflic acid ratio successfully controls the formation of the desired product.