Asymmetric cyclopropanation reactions via iron carbene complexes having chirality at the carbene ligand

Abstract

The reaction of Fp [(η5-C5H5)Fe(CO)2] anion (1) with chiral (+) or (−) o-anisaldehyde(tricarbonyl)chromium (2) in the presence of chlorotrimethylsilane produced the optically pure (+) or (−) bimetallic complex 4. Separate treatment of 4 at −78° C with trimethylsilyltriflate in the presence of styrene, followed by decomplexation with iodine, produced the corresponding cyclopropanes (101, cistrans). A 60% ee was indicated for the cis cyclopropanes.