Formal syntheses of (-)- and (+)-phalarine

Synthesis of the core structure of phalarine

Two new palladium-catalyzed reactions enabled the synthesis of the core structure of phalarine.

One-step formation of dihydrofuranoindoline cores promoted by a hypervalent iodine reagent

Treatment of aniline derivatives in the presence of a hypervalent iodine reagent and furan produces dihydrofuranoindoline cores in one step.

Facile access to 2,2-disubstituted indolin-3-ones via a cascade Fischer indolization/Claisen rearrangement reaction

From readily accessible arylhydrazines and allyloxyketones, 2,2-disubstituted indolin-3-ones could be obtained in good to excellent yields via a cascade Fischer indolization/Claisen rearrangement process.

[3 + 2]-Annulations of N-alkyl-3-substituted indoles with quinone monoketals catalysed by Brønsted acids

An organocatalytic dearomative [3 + 2]-annulation of 3-alkylindoles and quinone monoketals provided benzofuro[2,3-b]indolines, while the reaction with 3-phenylindole leads to 2,3-diarylindoles in moderate yields.

Synthesis of benzofuro[3,2-b]indoline amines via deamination-interrupted Fischer indolization and their unexpected reactivity towards nucleophiles

We report the access to the benzofuro[3,2-b]indoline framework via an interrupted Fischer indolization and its unexpected reactivity towards allyl nucleophiles.

Metal-free, one-pot conversion of proline derivatives into 2-aryl-3-iodo pyrrolidines by a sequential scission-iodination-arylation process

The metal-free, direct conversion of readily available proline derivatives into 2-aryl-3-iodopyrrolidines is carried out under mild conditions and in good yields, using a sequential radical decarboxylation-oxidation-iodination-arylation reaction. These iodinated pyrrolidines are valuable precursors of other compounds. For instance, they can be cyclized to tricyclic compounds or undergo dehalogenation to 2-aryl-2,5-dihydro-1H-pyrroles, which are iminosugar and 2-arylpyrrole precursors. This process provides a short pathway to a variety of alkaloid and drug analogues of potential pharmaceutical interest.

Direct oxidative coupling of N-acetyl indoles and phenols for the synthesis of benzofuroindolines related to phalarine

Inspired by the biogenetic synthesis of benzofuroindoline-containing natural products, we designed an oxidative coupling between phenol and N-acetyl indoles. This straightforward and direct radical process, mediated by 2,3-dichloro-5,6-dicyano-1,4-benzoquinone and FeCl3 allowed the regioselective synthesis of benzofuro[3,2-b]indolines, whose structure is found in the natural product phalarine.

Synthesis of the tetracyclic core of Illicium sesquiterpenes using an organocatalyzed asymmetric Robinson annulation

An enantioselective synthesis of the core framework of neurotrophic Illicium majucin-type sesquiterpenes is described here. This strategy is based on an organocatalyzed asymmetric Robinson annulation and provides an efficient approach for a diversity-oriented synthesis of Illicium natural products that holds remarkable therapeutic potential for neurodegenerative diseases.