Synthesis of ring-fused oxazolo- and pyrazoloisoquinolinones by a one-pot Pd-catalyzed carboxamidation and aldol-type condensation cascade process.

A three-component cascade process is described for the synthesis of ring-fused oxazolo- and pyrazoloisoquinolinones by a one-pot carboxamidation/aldol-type condensation reaction. The cascade process involves Pd-catalyzed carboxamidation of an aryl halide/active methylene compound with oxazolidinone or pyrazolidinone, and subsequent intramolecular base-catalyzed cyclization/dehydration through an aldol-type condensation process, to give ring-fused oxazolo- and pyrazoloisoquinolinones. This methodology provides an easy one-step approach to these important classes of nitrogen-containing heterocycles and can tolerate a wide array of functional groups, including ester, nitrile, methoxy, and halide.

Magnetic nanoparticle-supported proline as a recyclable and recoverable ligand for the CuI catalyzed arylation of nitrogen nucleophiles.

Magnetic nanoparticle-supported proline ligand was prepared and used for the CuI catalyzed Ullmann-type coupling reactions of aryl/heteroaryl bromides with various nitrogen heterocycles to form the corresponding N-aryl products in good to excellent yields; furthermore, this magnetic nanoparticle-supported proline ligand could be readily separated using an external magnet and reused without significant loss of activity.

Efficient construction of proline-containing ß-turn mimetic cyclic tetrapeptides via CuAAC macrocyclization.

A range of macrocyclic ß-turn mimetic tetrapeptides was prepared by efficient copper-tris(triazole) ligand complex catalyzed azide-alkyne "click" macrocyclizations in good to high yields. Preliminary conformational studies using X-ray crystallography and NMR spectroscopy demonstrated the presence of intramolecular H-bonds characteristic of ß-turns in these cyclic tetrapeptides.

CuAAC macrocyclization: high intramolecular selectivity through the use of copper-tris(triazole) ligand complexes.

A range of multivalent heteroaryl ligands, copper sources, and solvent systems have been investigated for use in CuAAC-mediated macrocyclization reactions. These studies have revealed the key factors governing selectivity for macrocyclization versus dimerization and identified a simple but specific set of reaction conditions capable of efficiently generating a diverse series of drug-like macrocycles at modest dilution in up to 95% yield.

Domino ring-opening/carboxamidation reactions of N-tosyl aziridines and 2-halophenols/pyridinol: efficient synthesis of 1,4-benzo- and pyrido-oxazepinones.

A domino process is described for the synthesis of 1,4-benzo- and pyrido-oxazepinones by one-pot sequential ring-opening/carboxamidation reactions of various N-tosylaziridines with a range of 2-halophenols/pyridinol under phase-transfer catalysis.

Palladium-catalyzed carboxamidation reaction and aldol condensation reaction cascade: a facile approach to ring-fused isoquinolinones.

Palladium-catalyzed carboxamidation reaction and aldol condensation reaction cascade are very useful for the synthesis of various ABC ring substituted fused isoquinolinones.