Synthesis of catenane structures via ring-closing metathesis

This study presents a detailed description of a synthetic strategy to obtai n catenane architectures through ring-closing metathesis. The approach is b ased on phenanthroline-based ligands containing terminal olefinic units tha t were designed to coordinate in a tetrahedral arrangement around a copper atom. Treatment of the assembled copper complexes with ruthenium catalyst 1 resulted in [2]catenates in high yields of 88-92%. Demetalation produced t he corresponding [2]catenand in nearly quantitative yields. Hydrogenation o f the catenates with Crabtree's catalyst and subsequent demetalation yielde d fully saturated catenands. The presently described procedure makes [2]cat enanes very accessible since the synthetic route consists of six steps (Sch emes 2 and 4) from commercially available 1,10-phenanthroline, the overall yield being 51%.