Anomalous Reactivity and Selectivity in the Intermolecular Diels–Alder Reactions of Multisubstituted Acyclic Dienes with Geometrical Isomers of Enals

Copper-Catalyzed Dehydrogenative Diels-Alder Reaction

A practical and effective copper-catalyzed dehydrogenative Diels-Alder reaction of gem-diesters and ketone with dienes has been established. The active dienophiles were generated in situ via a radical-based dehydrogenation process, which reacted with a wide variety of dienes to afford various polysubstituted cyclohexene derivatives in good to excellent yields.

Rhodium-Catalyzed Asymmetric [2 + 2 + 2] Cyclization of 1,6-Enynes with Aliphatic and Aromatic Alkenes

It has been established that a cationic rhodium(I)/(R)-MeO-BIPHEP complex catalyzes the asymmetric [2 + 2 + 2] cyclization of 1,6-enynes with aliphatic and aromatic alkenes to produce chiral cyclic dienes through β-hydride elimination from rhodacycle intermediates. Thus, obtained chiral cyclic dienes could be converted to chiral spirocompounds without racemization.

Silver-Catalyzed Domino Reaction of ortho-Carbonylated Alkynyl-Substituted Arylaldehydes with Conjugated Dienes: Stereoselective Access to Indanone-Fused Cyclohexenes

A silver-catalyzed domino reaction of ortho-carbonylated alkynyl-substituted arylaldehydes with conjugated dienes is described here. Through this reaction, the synthesis of a variety of indanone-fused cyclohexene derivatives can be achieved efficiently. The formation of these tricyclic products could involve a key Diels-Alder reaction of in situ generated indanenone dienophiles with conjugated dienes. Particularly, the products can be accomplished in a high endo/exo selective way.