Aldonolactones can be activated at the alpha and omega positions by selective bromination or tosylation. The activated aldonolactones can be transformed into epoxyaldonolactones by treatment with base under non-aqueous conditions. Treatment of epoxy- or bromodeoxyaldonolactones with aqueous base gives epoxyaldonates in which the epoxide can undergo Payne rearrangement to more stable epoxyaldonates. These can subsequently be opened by the carboxylate group with inversion of the configuration at the attacked carbon. Using this method a number of less available aldonolactones/acids have been prepared, in a reaction sequence where the configuration at one, two or three carbon centers has been stereospecifically interconverted. An attractive synthesis Of L-gluconic acid from D-gluconolactone is presented.
|Book series||Topics in Current Chemistry|
|Publication status||Published - 2001|