Methyl iodide nucleophilic reaction with rhodium

The rate-determining step in this process is the oxidative addition of methyl iodide to 1. Within the operating window of the process the reaction rate is independent of the carbon monoxide pressure and independent of the concentration of methanol. The methyl species 2 formed in reaction (2) cannot be observed under the reaction conditions. The methyl iodide intermediate enables the formation of a methyl rhodium complex methanol is not sufficiently electrophilic to carry out this reaction. As for other nucleophiles, the reaction is much slower with methyl bromide or methyl chloride as the catalyst component. 

The reaction has some similarity to the hydroformylation reaction described in Section 31-4B. The hydrogen iodide is required to transform methanol to methyl iodide. The rhodium catalyst then reacts with the methyl iodide as a nucleophilic reagent ... 

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