New methodologies in olefin metathesis: Dimer ring closing reactions and switchable catalysts

Ruthenium olefin metathesis is undoubtedly one of the most thriving fields in modern synthetic chemistry. Applications in industry and recent developments in basic research make the study of alkylidene ruthenium compounds both exciting and rewarding. As usually recurrent in organometallic catalysis, the development of novel ligands, in particular N-heterocyclic carbene ligands and alkylidenes, has had a pivotal role in the tremendous success of the area. During my talk I will introduce two of our contributions to this area; the first deals with the synthesis of bis-N-heterocyclic carbene ligands and the design of homo-bimetallic ruthenium complexes for their use in dimer ring-closing metathesis reactions (DRCM). In the second part I will show how strong sulfur chelation affects the activity, conformation and mechanism of ruthenium alkylidenes, and I will focus on novel photo-activation protocols for these latent catalysis.