Grubbs' Ruthenium-Carbenes Beyond the Metathesis Reaction: Less Conventional Non-Metathetic Utility

Robert H. Grubbs has developed powerful new catalysts, which is stable in air, for metathesis that enabled custom synthesis of many new molecules. The widely used Grubbs' ruthenium carbene Ru-1, well-known for its ability to promote olefin metathesis, is also an effective catalyst in radical atom transfer reactions such as Kharasch addition. Bicyclic ring systems can be prepared from acyclic dienes through a tandem RCM-intramolecular Kharasch addition reaction sequence. Studies in the group of Quayle have revealed that there is an important rate difference between olefin metathesis and Kharasch reactions in substrates exposed to both reactions conditions. This group suggested that the process requires either direct denaturation of complex Ru-1, which is itself formed as a byproduct of the initial metathesis cycle, or generation of a new ruthenium complex. New uses of the ruthenium-based catalyst are likely, and contribute to its relevance as a versatile and effective tool in organic and organometallic chemistry.