Chiral N-protected α-amino aryl-ketones are one of the useful precursors used in the synthesis of various biologically active compounds and can be constructed via Friedel-Crafts acylation of N-protected α-amino acids. One of the drawbacks of this reaction is the utilization of toxic, corrosive and moisture-sensitive acylating reagents. In peptide construction via amide bond formation, N-hydroxy...

friedel–crafts synthesis of triarylmethanes over 3-methyl-1-sulfonicacid imidazolium tetrachloroaluminate under green conditions:in this work, friedel–crafts (fc) alkylation of various arenes with aromatic aldehydes catalyzed by 3-methyl-1-sulfonic acid imidazoliumtetrachloroaluminate {[msim]alcl4}, as a green catalyst, to prepare triarylmethanes (tams) has been carried out. some aromatic aldeh...

Treatment of 1-(2-bromoarylmethyl)-3,4-dihydroisoquinolines with oxalyl chloride and triethylamine gave 1-(2-bromophenyl)-5,6-dihydropyrrolo[2,1-a]isoquinoline-2,3-dione derivatives, for example, 1-(2-bromophenyl)-5,6-dihydro-8,9-dimethoxypyrrolo[2,1-a]isoquinoline-2,3-dione. Radical cyclisation of these derivatives with tributyltin hydride and 1,1-azobis(cyclohexanecarbonitrile) afforded telis...

The first calcium-catalysed Nazarov cyclisation is described. The Ca(NTf2)(PF6) complex is found to be a very active catalyst for 4π electrocyclisations. The remarkable catalytic activity of this complex is attributed to its increased Lewis acidity compared to other Ca complexes. Spectroscopic studies have provided an insight into the chelating interactions between the substrate and the Ca cata...

Zethrene derivatives substituted by phenylethynyl groups bearing electron-donating and/or accepting groups were synthesised by iodine-induced transannular cyclisation of dehydrodinaphtho[10]annulene as the pivotal step followed by Sonogashira coupling reaction. Their physical properties were investigated to elucidate the effects of the substituents on the electronic configuration of the zethren...

Cyclotetrapeptides are important bioactive lead drug molecules that display a wide spectrum of pharmacological activities. However, the synthesis of cyclotetrapeptides from their linear precursors is challenging due to the highly constrained conformation required for cyclisation, thus hampering their progress to a clinical setting. This review provides an account of the reported methods used fo...

A range of heterocycles, namely thiazoles, imidazoles, imidazopyridines, thiazolidines and dimethoxyindoles, have been synthesised directly from alkenes via a two-step ketoidoination/cyclisation protocol. The alkene starting materials are themselves readily accessible using many different and well-established approaches, and allow access to a variety of heterocycles with excellent yields and re...

The tert-butyl hydroperoxide (TBHP)-promoted sequential carboxamidation and aromatisation of isonitriles with formamides was developed. This procedure tolerates a series of functional groups, such as methyl, fluoro, chloro, acetyl, methoxy carbonyl and cyano. This reaction involved the addition of formamide radicals to isonitriles and sequential C-C bond formation by intramolecular aromatic cyc...

Diethyl 2-fluoromalonate ester is utilised as a building block for the synthesis of 2-fluoro-2-arylacetic acid and fluorooxindole derivatives by a strategy involving nucleophilic aromatic substitution reactions with ortho-fluoronitrobenzene substrates followed by decarboxylation, esterification and reductive cyclisation processes.

A concise asymmetric synthesis of (+)-swainsonine (ent-1) is described starting from 2, which was readily prepared from commercially available l-glutamic acid. The method features installation of the indolizidine ring via an intramolecular cyclisation of α-sulfinyl carbanion as a key step. (+)-Swainsonine was obtained in 11.8% overall yield in 10 steps.