A sequential Claisen/ring-closing metathesis approach to the synthesis of spirocyclic cyclopentanes and cyclohexanes

A new method for the formation of spirocycles is described using a sequential Ireland–Claisen/Metathesis strategy to construct spirocyclic systems. Optimization of the Ireland–Claisen conditions provides the key metathesis substrates. The metathesis reactions were highly regioselective by virtue of steric hindrance in the substrate olefins.