[magician4]

A couple of things, first, I'm not convinced this is an alpha lactone reaction, though I don't know the mechanism. I'm guessing a clue may be found in the second reaction. I'm guessing dehydration to the acrylate. This is an interesting question though.

just a wild guess, as I was facing  the same mechanistic doubts with respect to [itex]\alpha[/itex]-lactone formation under these conditions: maybe   we have a case of [itex]\alpha[/itex] elimination here (the conditions seem rough enough to me) from HO-CH₂-COOK or even KO-CH₂-COOK , leading to :CH-COOK

this carben would insert in the indole ring (maybe with a cyclopropane-intermediate, which due to the harsh conditions would undergo ringopening  / hydride shift to the title compound)


would love to hear your comments on this

regards

Ingo

[discodermolide]

The original question was: can the conditions for making indole-3-acetic acid be used to make indole-3-
propionic acid?
I think the answer is no they can't.

Unless Magician4's conditions could apply.

[magician4]

Unless Magician4's conditions could apply.

i doubt that with a [itex] \beta [/itex]- hydroxyacid like 3-hydroxypropanoic acid  the formation of a carbene would be favoured: in that case the dehydratation towards acrylic acid (here: it's salt) should be favoured


regards

Ingo

[orgopete]

just a wild guess, as I was facing  the same mechanistic doubts with respect to [itex]\alpha[/itex]-lactone formation under these conditions: maybe   we have a case of [itex]\alpha[/itex] elimination here (the conditions seem rough enough to me) from HO-CH₂-COOK or even KO-CH₂-COOK , leading to :CH-COOK

this carben would insert in the indole ring (maybe with a cyclopropane-intermediate, which due to the harsh conditions would undergo ringopening  / hydride shift to the title compound)

I wasn't thinking carbene or rather I didn't think of it. Perhaps someone could look up whether carbene insertions give 3-substituted indoles? This may be well known, but just not to me.