In the synthesis of five-membered heterocycles by the annulation of epoxides with heterocumulenes such as carbon dioxide and isocyanates, we developed the indium-tin catalytic system and synthesized various cyclic adducts including novel types products under mild reaction conditions.

A facile synthesis of 4-indole benzofurans from the one-pot reaction of 4-alkyl-2-ynylphenols and indoles via a hypervalent iodine-induced oxidative dearomatization, a silver-catalyzed cascade Michael addition-annulation, and an aromatization is reported.

Highly functionalized dihydropyridinones were synthesized via the N-heterocyclic carbene-catalyzed enantioselective [4 + 2] annulation of α-chloroaldehydes and azadienes. Hydrogenation of the resulted dihydropyridinones afforded the corresponding piperidinones with high enantiopurity.

DABCO-catalyzed [3 + 2] annulation reaction of sulfamate-derived cyclic imines with isocyanoacetate proceeds under mild conditions, providing sulfamate-fused 2-imidazolines in moderate to excellent yields with moderate to excellent diastereoselectivities.

Annulation of thiophenes directly into the bay regions of rylene dyes through effective Stille coupling and subsequent ring-fusion under Scholl conditions leads to core-extended rylene tetracarboxylic diimides with interesting electro-optical properties.

We describe a straightforward protocol for a smooth dehydrogenative annulation reaction between various arenes and terminal alkynes using a catalytic amount of CuBr2 and molecular oxygen. 3-Methyleneisoindoline derivatives are prepared in high yields.

Hypervalent iodine(III)-induced oxidative [4+2] annulation of o-phenylenediamines and electron-deficient alkynes under metal-free conditions has been developed. The reaction allows for direct access to quinoxalines bearing two electron-withdrawing groups in an efficient manner.

The chiral N-heterocyclic carbene-catalyzed [3 + 2] annulation of α-bromoenals and 3-aminooxindoles was developed, giving the corresponding spirocyclic oxindolo-γ-lactams in good yields with high diastereoselectivities and enantioselectivities.

Tandem rhodium-catalyzed oxidative allylation and annulation of acetanilides with allyl acetate to afford the corresponding indoles are described. In addition, the site-selective C2 allylation, crotylation and prenylation of indoles using allylic acetates under rhodium catalysis are reported.

Recent advances in chiral-phosphine-catalyzed asymmetric annulation reactions; including annulations of allenes, alkynes, Morita-Baylis-Hillman (MBH) carbonates, and ketenes; and their applications in the synthesis of bioactive molecules and natural products are reviewed.