The nucleophilic addition of various nitrogen nucleophiles to the high
ly enantiomerically enriched a3-allyl)-tetracarbonyliron-(1+)-tetraflu
oroborate (2) (ee greater-than-or-equal-to 95%) leads after oxidative
removal of the tetracarbonyliron group to 4-amino-enoates (S)-3 of hig
h enantiomeric purity (ee = 95-98%). The reaction is highly regio- and
stereoselective and proceeds in good yields without isomerization of
the double bond.