Increased ring closing metathesis activity of ruthenium-based olefin metathesis catalysts coordinated with imidazolin-2-ylidene ligands

The novel air and water tolerant, imidazolinylidene-substituted ruthenium-b ased complex 3, has been prepared starting from RuCl2(=CHPh)(PCy3)(2) 2 and shown to exhibit increased ring-closing metathesis activity at elevated te mperature compared to that of the parent complex 2. Di-, tri-, and even tet ra-substituted cycloolefins were successfully prepared from corresponding d iene precursors using catalytic amounts of 3 in moderate to excellent yield s. (C) 1999 Elsevier Science Ltd. All rights reserved.