ON THE MECHANISM OF THE FE(CO)(5)-CATALYZED KHARASCH REACTION .2. REINVESTIGATION OF STEREOCHEMISTRY OF BRCCL3 ADDITION TO METHYL N-ACRYLOYL-(S)-PROLINATE

Addition of BrCCl3 to methyl N-acryloyl-(S)-prolinate (1) catalyzed by Ft(CO)(5) or Fe(CO)(5)-PPh(3) at 75-80 degrees C in benzene solution affords in good total yield methyl ((S)-2-bromo-3,3,3-trichlorobutyryl )-(S)-prolinate and methyl ((R)-2-bromo-3,3,3-trichlorobutyryl)-(S)-pr olinate (3) in an similar to 1.5:1 ratio, which does not depend on the catalytic system employed or its concentration. Catalysis by the Fe(C O)(5)-PPh(3) system substantially increases the adducts yield.