Ketals

[yellowjellybean]

Why can't ketals be formed from base catalysis?

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[Captain Sisko]

Why can't ketals be formed from base catalysis?

I'd imagine it has to do with the mechanism. something needs to protonate the carbonyl oxygen so it can get kicked out by the ethylene glycol. then you need to make the resulting oh group a good enough leaving group to get kicked out by the other end of your reactant. the first part of my answer may not be exactly right but i think the second part is.

 

[MedGrl@2022]

Why can't ketals be formed from base catalysis?

i need to check but I think H2O is usually the leaving group of ketals. In which case, it needs acids to protonate the oxygen. Thank you for reminding me that I need to review this. I hope to come back with the answer soon enough.

 

[yellowjellybean]

I reread some passages and I guess both ketals and acetals are unable to form under base conditions (it stops at the hemiketal and hemiacetal) which would make sense because OH cannot be protonated with base catalysis and it is not a good leaving group.