Regio- and Stereoselective Opening of Oxiranes through Neighbouring Group Participation: Stereocontrolled Synthesis of Enantiopure Hydroxylated Oxazolidin-2-ones

The regio- and stereo-selective ring opening of (S)-pyroglutaminol derived epoxides provides an effective route to protected syn,syn-aminodiol units. The procedure involves the chemoselective aminolysis or alcoholysis of (3R,4R,5R)-N-(tert-butoxycarbonyl)-3,4-epoxy-5-[(1-ethoxy)ethoxymethyl]pyrrolidin-2-one (10), followed by the formation in quantitative yield of oxazolidinone intermediates, through the mediation of neighbouring N-Boc groups. The practical synthetic interest of this route is illustrated by the example of (3R,4S,5R)-3,4-diacetoxy-5-(acetoxymethyl)pyrrolidin-2-one which should serve as useful building block in further syntheses.