AlCl3-mediated direct carbon-carbon bond-forming reaction of alpha-hydroxyketene-S,S-acetals with arenes and synthesis of 3,4-disubstituted dihydrocoumarin derivatives.

A simple and efficient AlCl(3)-mediated C-C coupling reaction between readily available alpha-hydroxyketene-S,S-acetals and various arenes via direct substitution of the hydroxy group in alcohols has been developed. On the basis of this C-C coupling reaction, a series of bio- and pharmacologically important 3,4-disubstituted dihydrocoumarins, difficult to obtain by other methods, were prepared in high yields by a sequential Friedel-Crafts alkylation and intramolecular annulation reaction of alpha-hydroxyketene acyclic-S,S-acetals with phenols under mild conditions.

Domino reaction of alpha-acetyl-alpha-carbamoyl ketene dithioacetals with Vilsmeier reagents: a novel and efficient synthesis of 4-halogenated 2(1H)-pyridinones.

A novel and efficient route to 4-halogenated N-substituted 2(1H)-pyridinones has been developed via a one-pot domino process of readily available alpha-acetyl-alpha-carbamoyl ketene dithioacetals with Vilsmeier reagents. These 4-halogenated-2(1H)-pyridinones constitute useful intermediates due to the easy elaboration on either the pyridinone core (by the displacement of the halogen atom) or functionality transformation (dithiocarbonyl functionality) and have proven to be a useful synthetic scaffold in the synthesis of the bio- and pharmacologically important fused-ring diazepine core.