A Facile Cross-Metathesis-Radical-CyclisationApproach to Monobenzannulated Spiroketals

The synthesis of a series of 5,5-, 5,6-, and 6,6-mono-benzannulated spiroketals using a novel cross-metathesis-radical-cyclisation approach is reported. Cross metathesis between two olefin coupling partners resulted in the formation of a heterodimer which upon hydrogenation furnished a saturated alcohol product. Oxidative radical cyclisation then afforded the desired monobenz-annulated spiroketals in good overall yield.