Substituted indenes can be synthesized via the Brønsted acid catalyzed cyclization of diaryl- and alkyl aryl-1,3-dienes. In this approach, treatment of symmetric or unsymmetric diaryl- and alkyl aryl-1,3-dienes with a catalytic amount of trifluoromethanesulfonic acid gives a variety of indene derivatives in good to excellent yields under mild conditions.

An efficient synthetic route to a wide range of trisubstituted pyrazines is developed from Rh-catalyzed reaction of 2H-azirines with N-sulfonyl-1,2,3-triazoles through the elimination of nitrogen molecule and arylsulfinic acid. The present reaction proceeds through formation of in situ generated dihydropyrazines.

An efficient synthetic method of 2-aryl-2H-benzotriazoles from nonprefunctionalized azobenzenes and N-sulfonyl azides via sequential Rh-catalyzed amidation (C-N bond formation) and oxidation (N-N bond formation) with PhI(OAc)2 in one pot is reported.

A rhodium-catalyzed cyclization using alkynes and arylphosphonic acid monoesters for the synthesis of phosphaisocoumarins is reported. A number of arylphosphonic acid monoesters were selectively cyclized in high yields with functional group tolerance. In addition, unsymmetrical alkynes are applied in high regioselectivity.

A highly efficient Pd-catalyzed ortho-alkenylation is reported using a mono-phosphoric acid-directing group for the first time. This phosphoric acid-directing group is successfully utilized for the synthesis of various alkenylated products and offers a new approach to transition-metal-catalyzed C-H activation.