Iron methylidene complexes

The formation of a stable (rj -C.G) ketene compound [(ri -CsHs) (C0)2Fe (CH2=C=0)][PF6 ] by carbonylation of an iron-methylidene complex ](ri -C5H5)(CO)2Fe+=CH2)][PF6 ] at 25 °C and 6 bar carbon monoxide pressure was described. Carbon-13 labeling study has shown that the electrophilic methylidene ligand picks up exogenous carbon monoxide and not a coordinated one [54]. 

Formation of a stable (t) -C,C) ketene compound (C5H5)Fe(CO)2(CH2CO)+PF6 by carbonylation of an iron-methylidene complex. A novel entry into CO-derived C2 chemistry. Journal of the American Chemical Society, 105, 5926-5928. 

In contrast to the neutral iron carbene complexes (47), cationic methylidene, ethyhdene, dimethylallylidene, andben-zylidene complexes (68) and (69) (Y = H, Me, CH=CMc2, Ph) react with alkenes to afford cyclopropanes in good yields (Scheme 23). h74,s4,93 ethylidene and benzyli-... 

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