Structural and configurational relationships 'metal complex-substrate-product' in asymmetric catalytic hydrogenation, hydrosilylation and cross-coupling reactions

摘要

The present-day published data on the relationships between the structures of rhodium, iridium, ruthenium, nickel and cobalt catalytic complexes and substrates in homogeneous asymmetric hyrogenation, hydrosilylation and cross-coupling reactions are systematised. The optimum ratio between the number of coordination vacancies in the complex and the number of functional groups of the substrate has been characterised in terms of a criterion of maximum enantioselectivity of the catalytic complex. The relationships between the configurations of the complexes and the products formed in the reactions are analysed. In the case of C_2-symmetrical chiral diphosphine complexes as catalysts (some structural elements of their ligands represent an incomplete turn of helix surrounding the central metal atoms), substrates of the same kind form the products having definite configurations characteristic of the particular orientation of the helix. For example, rhodium complexes with ligands that form an incomplete P-helical turn around metal atoms catalyse the formation of (R)-amino acids from the corresponding precursors. If the ligands contain fragments of M-helices around rhodium atoms, it is (S)-amino acids that are formed. The bibliograhy includes 234 references.