Novel indium-mediated deoxygenative α,α-diallylation of indole- and pyrrole-3-carboxaldehydes

1-Alkylindole-3-carboxaldehydes 1 and pyrrole-3-carboxaldehydes 2 on stirring with indium (2 equiv.) and allyl bromide (3 equiv.) in THF–H2O undergo deoxygenative diallylation at the carbonyl carbon to provide 3-[1,6-diene-4-yl]- indole 3 and pyrrole 4 derivatives. The formation of the normal 1,2-addition product in the case of 1d (R=COOEt) points towards the contribution of electronic factors due to the enamine double bond in the deoxygenation process.