Functional model oxygenations by nonheme iron complexes - Advances in Catalytic Activation of Dioxygen by Metal Complexes - page 178

reactivity with is difficult to apply the result to iron systems. In the extradiol
oxygenation, there are two possible ways of attachment of oxygen to aromatic
carbon, C1 or C6. Funabiki et al. have first proposed the attachment of oxygen to
C6 since the attachment at C1 has a possibility of both intra- and extradiol
cleavages. 87 However, Bugg et al. have preferred a common type of peroxo
intermediate (an oxygen adduct at C1) for both intra- and extradiol cleavages. 114, ll5,
158-163 Factors controlling the different migrations, i.e. acyl migration for intradiol
cleavage and alkenyl migration for extradiol oxygenation (Fig. 10), should be
clarified to support this mechanism.
Recently, Funabiki et al. have pointed out on the quantum chemical
calculation study that the species if formed tends to be
stabilized in its form rather than to break the O-O bond toward insertion of one O
atom to DTBC. 149 The alternative proposal is the attachment of an O atom of
between a C-C bond to form an epoxide-like species (Fig. 11). The probability
of this process should be discussed in future on the more elaborate calculations.