Syntheses of 2,5-disubstituted dihydrofurans from gamma-substituted chiral allenamides

reaction: see text] Details of a synthesis of dihydrofurans using gamma-substituted chiral allenamides are described here. Some transformations of these dihydrofurans are also examined including a highly stereoselective dihydroxylation and a rare account of a Lewis acid-mediated removal of an N-acyl substituent at the anomeric carbon of a tetrahydrofuran ring system. These studies provide further support for the synthetic utility of allenamides.