Ketal-tethered ring-closing metathesis. An unconventional approach to constructing spiroketals and total synthesis of an insect pheromone

An unconventional approach to constructing spiroketals via ring-closing metathesis of cyclic ketals is described here. This method possesses good generality with no loss of stereochemical integrity at the spiro center under standard RCM conditions. This approach has been applied to the synthesis of an insect pheromone to demonstrate its synthetic potential.