Novel clay-mediated, tandem addition-elimination-(MIchael) addition reactions of indoles with 3-formylindole: an eco-friendly route to symmetrical and unsymmetrical triindolylmethanes

摘要

Dry reaction of 3-formylindole (1) with indole (2a) on Montmorillonite K10 clay at room temperature furnished within minutes tris (indol-3-yl) methane (3a) in high yield. The reaction of 1 with other mono- and dialkylindoles (2b-c, skatole, 8a-c) under similar conditions yielded either or both or symmetrical (3b-c,9) and unsymmetrical (4b-c, 5b-c, 10,11a-c) triindolylmethanes.