A novel, copper(I)‐promoted azide–alkene aerobic oxidative cycloaddition protocol was developed for the regioselective synthesis of 1,4‐disubstituted/1,4,5‐trisubstituted 1,2,3‐triazoles by using azides and electron‐deficient olefins under an oxygen atmosphere.magnified image

The synthesis of indolo[1,2-a]quinazolinone starting from 2-iodobenzamide and indole derivatives is reported. In this two-step procedure, indole is N-arylated with 2-iodobenzamide derivatives via Ullman coupling, followed by an intramolecular C–H amidation using a palladium catalyst.

The synthesis of quinazolinone derivatives was achieved from 2‐iodobenzamide derivatives and various benzylamines, allylamine, and cinnamylamine derivatives through a one‐pot copper‐catalyzed reaction. In this reaction, the amine component (benzylamine/allylamine/cinnamylamine) is N‐arylated with 2‐iodobenzamide derivatives through Ullman coupling, followed by an intramolecular C–H amidation in the presence of copper catalyst.

A new and efficient protocol to prepare indenes is reported. Assisted by boron trifluoride diethyl etherate, the one-pot reaction of aryl homopropargyl alcohols and aldehydes in the presence of arenes yielded indene derivatives. The reaction was studied with various substrates, which suggests a cascade reaction including a sequence of Prins, Friedel-Crafts, ring-opening reactions, and Friedel-Crafts to form three C-C bonds leading to indenes.

A one-pot, two-staged protocol has been developed for the synthesis of 3-bromoindenes from aryl alkynyl alcohols/sulfonamides and aldehydes. Bromotrimethylsilane (TMSBr) initiated a halo-Prins cyclization reaction to give 3-(bromomethylene)-tetrahydropyrans or -piperidines, which underwent ring-opening and Friedel-Crafts allylation to yield 3-bromoindenes in the presence of Brønsted acids.