Synthesis of indole-cycloalkyl[b]pyridine hybrids via a four-component six-step tandem process.

The one-pot four-component reaction of 3-(1H-indol-3-yl)-3-oxopropanenitriles, aromatic aldehydes, cycloalkanones and ammonium acetate occurred via a six-step tandem Knoevenagel condensation-nucleophilic addition to carbonyl-Michael addition-N-cyclization-elimination-air oxidation sequence to afford structurally intriguing indole-cycloalkyl[b]pyridine-3-carbonitrile hybrid heterocycles in excellent yields.