Indium-mediated reduction of β-aminovinyl chloro-difluoromethylated ketones in the presence of heteroaryl aldehydes: A mild entry to novel difluoromethylene enaminone derivatives

The synthesis of new β-aminovinyl chloro-difluoromethylated ketones 1 and 2 is presented. In some of them the activation of the C–Cl bond was achieved, under mild conditions, using indium powder. The corresponding difluoro-enolates were trapped with a series of aromatic and heterocyclic aldehydes, to furnish the corresponding difluoromethylene aldol products 3 and 4, in moderate to good yields. The present synthetic methodology provides a convenient approach for the preparation of novel difluoromethylene functionalized enaminone derivatives.