Facile synthesis of fused polycyclic compounds via intramolecular oxidative cyclization/aromatization of ß-tetralone or ß-tetralone oximes.

A mild and efficient NBS promoted intramolecular oxidative cyclization/aromatization of ß-tetralone oximes has been explored. Under the optimized conditions, fused α-carbolines containing pentacyclic rings were obtained in moderate to good yields. Furthermore, various benzo[5,6]chromeno[2,3-b]indoles were successfully synthesized in moderate yields from ß-tetralones using slightly modified conditions. We proposed a possible reaction pathway based on the experimental results.

Synthesis of polycyclic spirooxindoles via an asymmetric catalytic one-pot stepwise Aldol/chloroetherification/aromatization procedure.

A general method for the synthesis of chiral pentacyclic spirooxindoles containing a tetrahydropyrano[2,3-b]indole scaffold through a one-pot stepwise sequence from 3-(3-indolomethyl)oxindole, paraformaldehyde and NCS is reported. Furthermore, the pentacyclic spirooxindoles could be transformed to bispirooxindole and other structurally diverse spirocyclic oxindoles.