A highly efficient and rapid entry to planar chiral 2-monosubstituted
diferrocenyl ketones is reported. Key step is the highly diastereoselective ortho-metalation of diferrocenyl ketone-SAMP-hydrazone,
followed by trapping with various electrophiles. The subsequent
racemisation-free cleavage of the chiral auxiliary affords the title
diferrocenyl ketones 4a-g with one exception in good to very good
overall yields and all with high enantiomeric excesses (ee = 97-99%).
asymmetric synthesis -
ortho-metalation - hydrazones - diferrocenyl ketones - planar
chirality