Fused Bis-lactams to Spirolactams: A New Member of the Family of Ring-Contraction Reaction

A new ring contraction of fused bis-lactams into spirolactams is presented here. In the presence of a triflate catalyst in various solvents under microwave irradiation, this rearrangement allows a clean conversion of some fused bicycles into spirocycles with good yields. The interest of this work thus lies in the use of activated 2,5-diketopiperazines as starting materials and demonstrates the wide range of applications of ring contraction reactions.