Preparation of rapidly initiating ruthenium based olefin metathesis catalysts

Z-selective olefin metathesis ruthenium catalysts are highly sought after, due to their wide applications in both pharmaceuticals and materials science. A crucial step towards the prepn. of rapidly initiating, Z-selective, olefin metathesis catalysts was found to be the addn. of sodium pivalate to phosphonium alkyidene catalyst 1, resulting in the formation of the C-H activated complex 2 after two days of heating. Prepn. of 2, a close analog to the target catalyst 4, promises that future synthesis of 4 should be facile.