(SIGMA-ALKYL)IRON COMPLEXES AS INTERMEDIATES IN (PORPHINATO)IRON-MEDIATED REDUCTION OF ALKENES AND ALKYNES WITH SODIUM-BOROHYDRIDE

The (porphinato)irons promote the reduction of alkenes and alkynes wit h NaBH4 in anaerobic benzene-ethanol. Styrene is reduced to 2,3-diphen ylbutane and ethylbenzene, whose precursors have been assumed to be th e (sigma-alkyl)iron(III) and -iron(II) porphyrin complexes, respective ly. The (sigma-alkyl)iron(III) porphyrin complex has the reactivity of the alkyl radical while the (sigma-alkyl)iron(II) porphyrin complex s hows the nature of the carbanion.