Divergent Aerobic Oxidative Ring-Opening Cascades of Isatins with 1,2,3,4-Tetrahydroisoquinoline

Construction of diverse spirooxindoles via a domino reaction of arylamines, but-2-ynedioates and 3-hydroxy-3-(indol-3-yl)indolin-2-ones

An iodine-promoted domino reaction of arylamines/benzylamines, dialkyl but-2-ynedioates and 3-hydroxy-3-(indol-3-yl)indolin-2-ones showed very interesting molecular diversity. The reaction in acetonitrile at 65 °C in the presence of 30% mmol I2 resulted in spiro[indoline-3,1'-pyrido[4,3-b]indoles] in satisfactory yields. When anilines without para-substituents were used in the reaction, a direct substitution of the hydroxyl group to 2-(phenylamino)maleate at the para-position of aniline gave chain products in good yields. Additionally, similar reactions with benzylamines not only gave spiro[indoline-3,1'-pyrido[4,3-b]indoles], but also afforded spiro[indoline-3,1'-pyrano[4,3-b]indol]-2-ones in lower yields. A plausible domino annulation mechanism was rationally proposed for the formation of different kinds of polycyclic compounds.

Molecular diversity of the acid promoted domino reaction of 3-hydroxy-3-(indol-3-yl)indolin-2-ones and cyclic mercapto-substituted β-enamino esters

The acetic acid promoted reaction of 3-hydroxy-3-(indol-3-yl)indolin-2-ones and mercapto-substituted β-enamino esters showed very interesting molecular diversity.

A One-Pot Ring-Opening/Ring-Closure Sequence for the Synthesis of Polycyclic Spirooxindoles

One-pot ring-opening/ring-closure process of combining methyleneindolinone with 3-aminooxindole has been developed in this work. Novel polycyclic spirooxindoles were efficiently assembled under mild conditions in high yields (up to 95 %) with moderate to good diastereoselectivities (up to >95:5 d.r.) through simple filtration.

Organocatalytic, Enantioselective, Polarity-Matched Ring-Reorganization Domino Sequence Based on the 3-Oxindole Scaffold

A one-pot squaramide-catalyzed enantioselective ring-reorganization domino sequence (Michael addition/intramolecular ring-opening/lactamization) of 3-hydroxyoxindole and methyleneindolinone, which can be readily derived from 3-oxindole, has been established in this work. As a result, novel polycyclic quinolinone-spirooxindoles bearing three contiguous chiral centers were efficiently and step-economically assembled under mild conditions in high yields (up to 97%) with excellent enantioselectivities (up to >99% ee) and moderate to good diastereoselectivities (up to >95:5 dr).

Construction of indeno[1,2-a]fluorene via domino reaction of 1,3-indanedione and 3-arylideneindolin-2-ones or chalcones

The base promoted domino reaction of 1,3-indanedione with 3-arylideneindolin-2-ones or chalcones afforded novel polysubstituted indeno[1,2-a]fluorenes.