Supramolecular double helical Cu(I) complexes for asymmetric cyclopropanation

Chiral double-stranded helicates, formed between Cu(I) ion and C-2-symmetric oligopyridines, were used for catalytic asymmetric cyclopropanation of alkenes; low catalyst loadings (0.2 mol%), high TONs (up to 404) and short reaction times ( 30-60 min) were achieved with [Cu2L2]OTf2 (L=chiral C-2-symmetric terpyridine).