Selective hydrogenation of 4,5-dihydro-1,3-oxazin-6-ones to carbaldehyde derivatives; chemical differentiation between acylazetidin-2-ones and the corresponding isomeric oxazin-6-ones

Abstract

Catalytic hydrogenation of optically active and non-active dihydro-oxazin-6-ones unexpectedly led to preferential reduction of the carbonyl group with ring-opening yielding carbaldehyde derivatives. This reaction resolved a structural problem by leading to the positive characterisation of an isomeric acylazetidin-2-one and the corresponding dihydro-oxazin-6-one.