The reactivities of dehydroalanine derivatives towards 1,3-dienyl cobaloxime complex: new routes to functionalised carbocyclic amino acids

The reactivities and selectivities of the Diels–Alder reactions of acyclic dehydroalanine esters and cyclic dehydroalanines derived from piperazine-2,5-diones with 1,3-dienyl cobaloxime complex are reported. From our studies we demonstrate the use of the activated organocobalt diene in a ‘combinatorial’ approach to the synthesis of functionalised cyclic amino acids and derivatives from a single cycloaddition reaction.