Intramolecular [3 + 2]-cycloadditions of azomethine ylides derived from secondary amines via redox-neutral C-H functionalization

Tandem approach for the synthesis of 3-sulfenylimidazo[1,5-a]pyridines from dithioesters

Iodine-mediated synthesis of 3-sulfenylimidazo[1,5-a]pyridines via C–H functionalization has been achieved using dithioesters, 2-methylaminopyridines and sulfonyl hydrazides.

The Rügheimer-Burrows reaction revisited: Facile preparation of 4-alkylisoquinolines and 3,5-dialkylpyridines from (partially) saturated amines

A long-known class of cyclic amine/aldehyde condensation reactions was reinvestigated. Benzoic acid was found to efficiently promote condensations of amines such as piperidine or 1,2,3,4-tetrahydroisoquinoline with aromatic aldehydes, resulting in amine β-functionalization and aromatization. These redox-neutral transformations provide 3,5-dialkylpyridines and 4-alkylisoquinolines in moderate to good yields, following short reaction times under microwave conditions.

Highly diastereoselective synthesis of polycyclic amines via redox neutral C–H functionalization

Construction of polycyclic amines via C–H functionalization and 3+2 cycloaddition with high diastereoselectivities was achieved under mild conditions.

Metal-free cycloaddition to synthesize naphtho[2,3-d][1,2,3]triazole-4,9-diones

A metal-free domino [3 + 2] cycloaddition is reported to construct naphtho[2,3-d][1,2,3]triazole-4,9-dione derivatives and provide an alternative approach to the azide–alkyne cycloadditions.

Diastereoselective synthesis of fused oxazolidines and highly substituted 1H-pyrrolo [2,1-c][1,4] oxazines via C–H functionalization

The first one pot protocol for the diastereoselective synthesis of oxazolo[2,3-c]isoquinoline was achieved by metal-free, benzoic acid catalyzed reactions under mild conditions via C–H, C–O bond functionalization.