The concept of a “hidden intermediate” in a reaction pathway has been promoted by Dieter Cremer[1] and much invoked on this blog. When I used this term in a recent article of ours[2], a referee tried to object, saying it was not in common use in chemistry. The term clearly has an image problem. A colleague recently sent me an article to read (thanks Chris!) about isotope effects in the epoxidation of ethene[3] and there I discovered a nice example of hidden intermediates which I share with you now.
References
- E. Kraka, and D. Cremer, "Computational Analysis of the Mechanism of Chemical Reactions in Terms of Reaction Phases: Hidden Intermediates and Hidden Transition States", Accounts of Chemical Research, vol. 43, pp. 591-601, 2010. https://doi.org/10.1021/ar900013p
- H.S. Rzepa, and C. Wentrup, "Mechanistic Diversity in Thermal Fragmentation Reactions: A Computational Exploration of CO and CO<sub>2</sub> Extrusions from Five-Membered Rings", The Journal of Organic Chemistry, vol. 78, pp. 7565-7574, 2013. https://doi.org/10.1021/jo401146k
- T. Koerner, H. Slebocka-Tilk, and R.S. Brown, "Experimental Investigation of the Primary and Secondary Deuterium Kinetic Isotope Effects for Epoxidation of Alkenes and Ethylene with <i>m</i>-Chloroperoxybenzoic Acid", The Journal of Organic Chemistry, vol. 64, pp. 196-201, 1998. https://doi.org/10.1021/jo981652x