When methyl manganese pentacarbonyl is treated with carbon monoxide in e.g. di-n-butyl ether, acetyl manganese pentacarbonyl is formed. This classic experiment conducted by Cotton (of quadruple bond fame) and Calderazzo in 1962[1] dates from an era when chemists conducted extensive kinetic analyses to back up any mechanistic speculations. Their suggested transition state is outlined below. Here I subject their speculations to a quantum mechanical “reality check“.
References
- F. Calderazzo, and F.A. Cotton, "Carbon Monoxide Insertion Reactions. I. The Carbonylation of Methyl Manganese Pentacarbonyl and Decarbonylation of Acetyl Manganese Pentacarbonyl", Inorganic Chemistry, vol. 1, pp. 30-36, 1962. http://dx.doi.org/10.1021/ic50001a008