Turning the Light On: Recent Developments in Photoinduced Olefin Metathesis

Olefin metathesis is one of the most important methods to form carbon-carbon double bonds and has found many applications in industry and academia. The ability to initiate the reaction using external stimulus such as light, with high spatial and temporal resolution is highly advantageous and provides creative novel opportunities in organic syntheses and material sciences. This review article covers recent advances in light-activated olefin metathesis reactions from the development of novel complexes that can be initiated photochemically to recently reported applications of photoinduced olefin metathesis, as well as the bright newly emerging field of photoredox-mediated metal-free ROMP. 1 Introduction 2 Light-Activated Olefin Metathesis Complexes 2.1 Sulfur-Chelated Hoveyda-Grubbs-Type Complexes 2.2 Nitrogen-Chelated Hoveyda-Grubbs-Type Complexes 2.3 Catalyst Activation with Photoacid Generators 2.4 Phototuning of Active Complexes 2.5 Photoactivation of Non-Grubbs-Type Olefin Metathesis Complexes 3 Photoredox-Mediated Metal-Free ROMP 4 Applications of Photoinduced Olefin Metathesis 4.1 Chromatic Orthogonal Olefin Metathesis 4.2 UV-Filter-Assisted Olefin Metathesis 4.3 Photolithographic Olefin Metathesis Polymerization 5 Conclusions.