Base Induced Chiral Substituted Furans and Imidazoles from Carbohydrate-Derived 2-Haloenones.

Chiral substituted furans and imidazoles are key intermediates to access biologically important molecules. We describe herein a catalyst/ligand free cascade Michael-type addition/intramolecular cyclization/carbohydrate-ring opening of 2-haloenones with 1,3-dicarbonyl compounds or amidines utilizing K2CO3/DMSO at ambient temperature that provides a straightforward approach to a variety of optically active (poly)hydroxy furans and imidazoles containing multiple stereocenters with good yield and excellent regioselectivity. The furan intermediates provide efficient access to synthetically valuable substituted α-benzyloxyvinyl ketones. The NMR spectrum of the substituted 2-methylfurans shows an unusual long-range ((5)JH-H) (1)H-(1)H COSY cross-peak between C2-CH3 and C4-H signals.