In the previous post,[1] I was commenting that the transition state for borohydride reduction of a ketone contained some close contacts between the hydrogen of the borohydride and the hydrogen of water. A systematic search of the CSD reveals a modest number of such contacts have been observed in crystal structures (Table). Since it is always good to have a reality check for constructed transition states, here I take a look at some of compounds showing the closest H…H contacts in the experimental database of structures.
References
- H. Rzepa, "The mechanism of borohydride reductions. Part 2: 4-t-butyl-cyclohexanone – Dispersion induced stereochemistry.", 2025. https://doi.org/10.59350/x5k75-t2m40