Aren't hydrogens on less substituted groups more electrophilic?
Answers
yes hydrogens are more electrophilic when on less substituted groups
We know that, in case of a choice, catalytic hydrogenation will hydrogenate the less substituted alkene, because the less substituted alkene is less stable. But, we also know that, in case of a choice, peroxyacids perform epoxidation of the more substituted alkenes, because the latter are more electron-rich (i.e. more nucleophilic) (details) In one case, we are favoring the stability of the pi bond. But in another case, we are prioritizing the nucleophilicity of the pi bond. I believe this definitely has something to do with their respective mechanisms, which I've studied from Libretexts (hydrogenation and epoxidation). The only difference I see is that in hydrogenation, the pi bond first attaches to the catalyst surface, and then a hydrogen atom (already attached to that surface) is transferred to the pi bond. But, in epoxidation, the alkene directly attacks the electrophilic −OH−OH group of the peroxy acid.