Triple Nucleophilic Head-to-Tail Cascade Polycyclization of Diazodienals via Combination Catalysis: Direct Access to Cyclopentane Fused Aza-Polycycles with Six-Contiguous Stereocenters.

Reported herein are the bench stable (24)-diazohexa-2,4-dienals (diazodienals) and their unprecedented polycyclization with aldimine and arylamines enabled by Rh(II)/Brønsted acid relay catalysis. This scalable and atom-economical reaction provides direct access to the biologically important azatricyclo[6.2.

An unprecedented benzannulation of oxindoles with enalcarbenoids: a regioselective approach to functionalized carbazoles.

A novel Rh(ii)/Brønsted acid catalyzed tandem benzannulation of oxindoles with enaldiazo carbonyls led to the formation of valuable 1-hydroxy-2-acylcarbazoles. This reaction is proposed to involve a formal insertion of a rhodium enalcarbenoid into an oxindole sp(2) C-O bond, an oxa-Michael addition, Friedel-Crafts reaction and a semipinacol type 1,2-carbonyl migration.

Regioselective π-extension of indoles with rhodium enalcarbenoids--synthesis of substituted carbazoles.

An efficient Rh(II) carboxylate and Brønsted acid catalyzed direct π-extension of indoles to 4-substituted carbazoles is developed. The reaction involves a regioselective C-3 functionalization of indole by a rhodium enalcarbenoid and a Brønsted acid assisted cyclocondensation. In addition a twofold regioselective π-extension of pyrroles to 4,8-disubstituted carbazoles has also been developed.