Synthesis of highly substituted pyroglutamates via a domino Michael addition-Claisen rearrangement-lactamisation approach.

Chelated enolates are versatile nucleophiles for Michael additions to alpha,beta-unsaturated allylic esters. By quenching the reaction with TMSCl and heating a subsequent Ireland-Claisen rearrangement can occur. Direct cyclisation of the rearrangement product gives rise to highly substituted pyroglutamic acid derivatives.