Asymmetric organocatalytic vinylogous Michael addition triggered triple-cascade reactions of 2-hydroxycinnamaldehydes and vinylogous nucleophiles: Construction of Benzofused Oxabicyclo[3.3.1]nonane Scaffolds

An organocatalytic vinylogous Michael addition triggered triple-cascade reaction has been developed. 2-Hydroxycinnamaldehydes worked under iminium activation with either acyclic or cyclic ketone-derived α,α-dicyanoalkenes, yielding the benzofused oxabicyclo[3.3.1]nonanes bearing one quaternary...

Acid-Mediated Denitrogenation/Rearrangement/Coupling of ­Benzyl Azides with Triazolyl-Substituted Cycloalkanones

Organic molecules containing α-triazolyl or β-amino cyclic ketone fragments have been individually proven to show good bioactivities and to be useful in asymmetric and pharmaceutical syntheses. A triflic acid-promoted simple and efficient method for the synthesis of unsymmetrical α-triazolyl-α′-(aminomethyl)cycloalkanones from benzyl azides and α-triazolylcycloalkanones has been developed. A series of unsymmetrical α,α′-disubstituted cycloalkanones were obtained with high syn-diastereoselectivity and up to 82% yield. Examination of the reaction mechanism showed that the benzyl azides undergo protonation, nitrogen elimination, rearrangement, and electrophilic attack by the enol forms of the cyclic ketones.

Synthesis of β-Selenylated Cyclopentanones via Photoredox-Catalyzed Selenylation/Ring-Expansion Cascades of Alkenyl Cyclobutanols

A photoredox strategy to access β-selenated cyclic ketone derivatives through the coupling reaction of 1-(1-arylvinyl)cyclobutanols with diselenides under blue LED irradiation and an air atmosphere was developed. This reaction employs the easily accessible and shelf-stable diselenides as a selenium radical source, and the reaction has advantages of mild reaction conditions and broad substrate scope.

Metal-Free Mild Synthesis of Novel 1′H-Spiro[Cycloalkyl-1,2′-quinazolin]-4′(3′H)-ones by an Organocatalytic Cascade Reaction

A concise organocatalytic method for the facile synthesis of some novel 1′H-spiro[cycloalkyl-1,2′-quinazolin]-4′(3′H)-ones via a one-pot, three-component condensation of isatoic anhydride, aryl or aliphatic amines and a cyclic ketone is described.