An enantiospecific synthesis of allosamizoline

An enantiospecific synthesis of allosamizoline 4, the aglycone of the chitinase inhibitor allosamidin 3, has been achieved, starting from readily available glucosamine. The key step in the synthesis involves the cyclisation of a carbon-centred radical onto a suitably positioned oxime ether group, thus effectively converting a carbohydrate derivative into a highly functionalised cyclopentane.