Selective synthesis of polyfunctionalized pyrido[2,3-b]indoles by multicomponent domino reactions.

A series of novel polyfunctionalized pyrido[2,3-b]indoles were synthesized by three- or four-component domino reactions under microwave irradiation. This protocol has the advantages of readily available starting materials, short reaction times, high yields, easy workup, and high chemo- and regioselectivities.

Microwave-assisted improved synthesis of pyrrolo[2,3,4-kl]acridine and dihydropyrrolo[2,3,4-kl]acridine derivatives catalyzed by silica sulfuric acid.

An improved synthesis of multifunctionalized pyrrolo[2,3,4-kl]acridine derivatives with different substituted patterns using silica sulfuric acid (SSA) as a heterogeneous catalyst under microwave irradiation conditions was developed. The reaction could be conducted by using readily available and inexpensive substrates within short periods of 12-15 min. under microwave irradiation. Compared with the conventional methods, the remarkable advantages of this method are milder reaction conditions, operational simplicity, higher yields, short reaction times, and an environmentally friendly procedure.

Highly efficient construction of pentacyclic benzo[b]indeno-[1,2,3-de][1,8]naphthyridine derivatives via four-component domino reaction.

A series of new octahydrobenzo[b]indeno[1,2,3-de][1,8] naphthyridine and decahydropyrido[2,3,4-gh]phenanthridine derivatives were synthesized via a four-component domino reaction under microwave irradiation. This one-pot transformation, which involved multiple steps and did not require the use of a catalyst, constructed four new C-C bonds, two new C-N bonds, and three new rings, with efficient use of all reactants.

Facile, efficient, and diastereoselective synthesis of heterohelicene-like molecules.

A concise and efficient route to new and interesting heterohelicene-like molecules has been developed through the one-pot, cascade reductive coupling reaction of o-hydroxydiimines or o-nitrodiimines and triphosgene in the presence of TiCl4/Sm. Purification of the final products only required a single recrystallization leading to high purity. High diastereoselectivity was also achieved, and two structures of the final products were confirmed by X-ray diffraction analysis.