The proposed programme will use a number of synthetically accessible systems to improve our quantitative understanding of the organic reaction mechanism of the alkene ring closing methathesis (RCM) and cross metathesis (CM) reactions. We wish to determine effective molarities (EMs) as a function of ring size n and substitution patterns, to measure absolute cyclisation and oligomerisation rates, and to use computational methods to understand these data. The programme will develop expertise and tools in physical organic chemistry (experimental kinetics, computational methods) while investigating a reaction of considerable fundamental importance and acute current relevance. We propose to use computational and experimental kinetic techniques synergistically to refine and/or challenge fundamental and general ideas about aspects of the mechanism of RCM reactions, bringing the reaction within the domain of expertise of POC. We also wish to develop complementary insight concerning cross metathesis (CM) reactions, insights which are required if we are to understand the issues surrounding cyclisation efficiency fully. The successful delivery of this programme will advance research knowledge significantly and make a considerable contribution to UK standing in the important and topical field of alkene metathesis chemistry.