1-Oxa-3-azapentalen-2-ones as precursors of cis-2-amino alcohols: synthesis from acetylenic alcohols, carbon dioxide and amines via intramolecular amidoalkylation of oxazolidinones

The reaction of 4-methyl-4-(4-methyl-3-pentenyl)-5-methylen-1,3-dioxolan-2-one 1a with primary amines 2 leads to the corresponding 4-hydroxy-4-methyloxazolidin-2-ones 3 which are transformed by intramolecular amidoalkylation into 1-oxa-3-azapentalen-2-ones 4 and 5, potential precursors of cyclopentane cis-2-amino alcohols.