Recent advancements in ring closing olefin metathesis

A shea overview on recent developments in ring closing metathesis (RCM) of 1,omega-dienes to cycloalkenes is provided, with particular emphasis on applications to natural product synthesis and the preparation of olfactory perfume ingredients. These examples show that RCM is becoming a mature tool for the formation of carbo-and heterocycles of any size greater than or equal to 5, including medium and large ring compounds which are difficult to prepare otherwise. Although the reactivity profile of the standard metathesis (pre)catalysts cannot be reduced to a simplistic picture, their excellent compatibility with an army of functional groups will be outlined.