Attempts at generating metathesis-active Fe(IV) and Co(IV) complexes via the reactions of (silox)2M(THF)2, [(silox)3M][Na(THF)2] (M = Fe, Co), and related species with propellanes and triphenylboron

[Display omitted] Metathetical syntheses of (silox)2M(THF)2 (1-M, Fe, Co), [(silox)3M]Na(THF)2 (2-M, Fe, Co), and (silox)3Fe(THF) (3) are presented, as are X-ray structural studies of 1-Co, 2-Fe, and 2-Co. Exposure of these complexes to 1.1.1-propellane (111P, C5H6) and 1,3-dehydroadamantane (AdP), which are known progenitors of ROMP-active alkylidenes with ruthenium, failed to elicit similar reactivity. A total of 28 complexes were subjected to 111P in attempts to make “Fe(IV)” alkylidenes capable of some form of olefin metathesis with no success. At best, catalytic ring-opening to 3-exo-methylene cyclobutylidene was evidenced. The addition of triphenylboron as a Lewis acid failed to aid in metal complex formation of the propellanes, but an unusual rearrangement of AdP was noted. In addition, 2-Fe catalyzed the conversion of 111P to 3-exo-methylene cyclobutylidene, which added twice to Ph3B, affording a structurally characterized product, Ph(κ-CH=CMeCH2BPh(cC4H4-1-Ph,3-CH2) (4), which features cyclobutyl-ring-opening, migration, and phenyl migration.