Organometallische Komplexverbindungen IX. Steuerung der optischen Induktion

Article abstract of DOI:10.1016/0022-328X(89)87057-3

Bis(μ-methyl-1,3-dimethyl-η³-allyl-nickel) which has been modified with chiral P ligands react with carbon monoxide to give the optically active 3-methyl-E-4-hexene-2-one.Low-temperature studies (DSC, 13C NMR) have indicated that this reaction is too fast to observe any intermediates.A suitable phosphine was chosen so that the chiral substituent is kept constant (1R,3R,4S-(-)-menthyl) and the other two are of the same, mostly achiral type (either P(-)MenthX2 or P(O(-)Menth)X2), the extent and direction of optical induction depends strongly on the concentration and the type of P ligand examined.Furthermore, changes in achiral parts of the P ligand after special order factors can lead to conversion into the excess enantiomer.Up to now the usual strategy to obtain the optical antipode has been to change the chirality of the educt.Therefore both enantiomers may be necessary.In our case only chiral precursor is needed and for this reason there is less need to draw from the natural pool, which should be useful for asymmetric synthesis.