The pyroglutamate hydantoin rearrangement

When a mixture of a pyroglutamate and an isocyanate in THF is treated with NaH, a ring transformation occurs leading to functionalised hydantoins. The novel reaction involves a ring-closing ring-opening sequence providing a new and straightforward access to an interesting class of heterocyclic compounds. Furthermore, starting from pyroglutamates allows the synthesis of highly substituted hydantoins under very mild conditions. This ring transformation in combination with ring-closing metathesis is used in a four-step reaction sequence for the synthesis of multi-functionalised bicyclic hydantoin derivatives.