Chirality preservation in pyrrolinone iron tetracarbonyl complexes ? a route to enantiopure 5-substituted pyrrolinones

The enantiopure iron complex 4 reacts under the influence of BF3·OEt2 with allylsilanes and enol acetates through a cationic intermediate in which the chirality of 4 is preserved, yielding enantiopure 5-substituted 3-pyrrolin-2-ones.