Novel indium-mediated ternary reactions between indole-3-carboxaldehydes–allyl bromide–enamines: facile synthesis of bisindolyl- and indolyl-heterocyclic alkanes

Indole-3-carboxaldehydes undergo indium-mediated ternary reactions with allyl bromide and indoles to provide symmetrical and unsymmetrical bisindolyl alkanes and with other heterocyclic enamines viz. pyrrole, pyrazole, 6-aminouracil and imidazole to provide indolyl-heterocyclic alkanes in excellent yields. The reactions with substituted allyl bromides proceed with greater ease.