New synthesis of 4,5-dihydro-1,3-oxazoles and 4,5-dihydro-1,3-oxazines, useful intermediates to enantiomerically pure amino diols. X-Ray molecular structure of (4S,5R,4′S)-1 -(4′-lodomethyl-4′-methyl-4′,5′-dihydro-1′,3′-oxazol-2′-yl)-3,4-dimethyl-5-phenylimidazolidin-2-one and (4S,5R,4′S,1″S)-1 -[4′-(1″-iodobutyl)-4′,5′-dihydro-1′,3′-oxazol-2′-yl]-3,4-dimethyl-5-phenylimidazolidin-2-one

Abstract

The iodocyclization of O-alkenyl imidates derived from (4R,5S)-1,5-dimethyl-4-phenylimidazolidin-2-one (1) affords diastereoisomeric mixtures of 4,5-dihydro-1,3-oxazoles (7a and b) and (9a and b) or 4,5-dihydro-1,3-oxazines (8a and b) and (10a and b) which are easily separated by flash chromatography and successively cleaved to enantiomerically pure amino diols. Crystal structures were determined for compounds (7a) and (9a).