Novel chemoenzymatic synthesis of an enantiopure allo-inosamine hexaacetate from benzyl azide

Abstract

A facile and short chemoenzymatic synthesis of (−) 1L-5-amino-5-deoxy-allo-inositol hexaacetate is described using benzyl azide as starting material. The key transformations consist of an enzymatic dioxygenation using the toluene dioxygenase enzymatic complex, followed by an allylic azide double sigmatropic [3,3] shift to introduce the nitrogen functionality in the ring in a stereoselective manner. Azide reduction and further regioselective oxidation of the diene moiety afforded the desired inosamine in only eight steps from benzyl azide.