The enantioselective fluoroacetamide acetal claisen rearrangements of N-fluoroacetyl-trans-(2R,5R)-2,5-dimethylpyrrolidine

Optically active monofluorinated amides were prepared via the amide acetal Claisen rearrangement and the establishment of the absolute stereochemistry of the rearranged products proved that the chiral auxiliary directed the approach of the crotyl fragment to the Si face of the ( E )- N,O -ketene acetal. The general utility of this type of rearrangement is also discussed.