Aminocarbonyl group containing Hoveyda-Grubbs-type complexes: Synthesis and activity in olefin metathesis transformations

Three novel "boomerang" precatalysts bearing different aminocarbonyl functions are reported. Comparative kinetic studies show that this functional group allows for a control of the catalytic activity in metathesis transformations. The scope of the more active catalyst is investigated and shows a good tolerance to various substrates in ring-closing metathesis, enyne metathesis, and cross metathesis. ICP-MS analyses illustrate the good affinity of this catalyst for silica gel, as levels of Ru contamination lower than 6 ppm are detected in the final products.