ON THE MECHANISM OF THE FE(CO)(5)-CATALYZED KHARASCH REACTION .1. STEREOCHEMISTRY OF ADDITION OF BRCCL3 TO (R)-3-(E)-CINNAMOYL-4-PHENYLOXAZOLIDIN-2-ONE, (R)-3-(E)-ACRYLOYL-4-PHENYLOXAZOLIDIN-2-ONE, AND THEIR PI-COMPLEXES WITH FE(CO)(4)

Regioselectivity and diastereoselectivity of the addition of BrCCl3 to (R)-3-(E)-cinnamoyl-4-phenyloxazolidin-2-one (1) and (R)-3-(E)-acrylo yl-4-phenyloxazolidin-2-one (2) catalyzed by Fe(CO)(5) or initiated wi th benzoyl peroxide were investigated. Stereochemistry of the reaction of BrCCl3 with the pi-complexes (4R,alpha S,beta nnamayl-4-phenyloxat olidin-2-one)irontetracarbonyl (3a) and (4R,alpha R)-eta(2)-(3-acryloy l-4-phenyloxazolidin-2-one) irontetracarbonyl (4b) was also studied, T he results obtained allow the following conclusions to be drawn: (1) t he thermal Kharasch reaction catalyzed by Fe(CO)(5) proceeds by a redo x catalysis mechanism; (2) iron (in any of its oxidation states) is no t coordinated to olefins in the transition stare of the reaction; (3) the transfer of the halogen atom on the radical adduct probably occurs inside a radical-iron cation pair.