Functionalization by Formal C-O Reductive Eliminations

The reactions with are stoichiometric but cleanly convert methane to methanol by the general reaction shown in Eq. 4. 

The reaction with Au(III) is interesting in that Au(0) is generated with clean formation of CH3X by the stoichiometry shown in Eq 5. 

As noted in Fig. 7.36, if the Au(0) could be reoxidized it should be possible to make the systems catalytic. In considering possible oxidants it was necessary to ensure that the reoxidation reaction would not destroy the methanol product and that the acidity of the solvent would not be reduced by the presence of the oxidant. A good choice is selenic acid, H2Se04- This acid is almost as strong as sulfuric acid but is a much more powerful oxidant and importantly is known to dissolve gold metal. Using this reagent we have found that the Au(III) system 

The reaction is quite clean as shown by the NMR of crude reaction mixture from the reaction carried out with 100% enriched CH4. 

We have recently found that this reaction is feasible and can be carried out with both the (bpym)PtCl2/H2S04 system as well as with Pd(II) in sulfuric acid [30]. The reaction with Pd(II) is very interesting because, while this system can catalyze the additional oxidative insertion of CO into a CH bond of methane, it 

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