Design, synthesis and reactivity of N-adamantyl cyclometalated cyclic(alkyl)(amino)carbene ruthenium complexes in Z-selective olefin metathesis

Abstract

The synthesis of a Z-selective ruthenium complex featuring a cyclic(alkyl)(amino)carbene (CAAC) ligand is reported. Its preparation proceeds through a selective intramolecular C(sp3)-H activation at the N-adamantyl substituent of the CAAC ligand featuring a key spiro-tetraline moiety. The resulting cyclometalated precatalyst was isolated in good yield and fully characterized by X-ray diffraction analysis. This catalyst displays high Z-selectivity (up to 95:5 Z/E ratio) in both self-metathesis (SM) and cross-metathesis (CM) reactions.