thors.lab - 23-8-2020 at 23:29
In TiHKAL, Sasha forms indol-3-ylglyoxyl chloride by reacting oxalyl chloride with indole directly, usually in EtOEt. I was curious about the
mechanism behind this, but the only thing I could find was this which just reaffirms that it works: https://doi.org/10.1021/ja01652a113
This is not a Friedel-Crafts acylation because it doesn't use a Lewis acid to form the electrophile, right? So what's happening? I could only find
sources generally adding acyl chlorides by using something like Et2AlCl (as seen here https://doi.org/10.1021/ol005841p)
Thanks,
Thor
karlos³ - 24-8-2020 at 03:31
As far as I know, it is still an electrophilic acylation, just not a FC one.
But it works like a charm, I have done it too.
draculic acid69 - 24-8-2020 at 04:23
And how long did you smell like indole afterwards?
karlos³ - 24-8-2020 at 04:43
Me? Not at all actually.
Even the intermediary indolglyoxylamides don't smell much, certainly much less than indole itself.
Indole is really not that bad, I mean its not skatole or so 
But then again, everytime I've worked with indole, I only did so in quantities of a few grams.
Neither do 5-bromo- or 5-methoxyindole smell bad, nor even strong, less so than plain indole actually.
thors.lab - 24-8-2020 at 13:19
So the carbonyl carbon in oxalyl chloride is electrophilic enough to attack the indole C3 without some acid turning it into a carbocation? I suppose
this makes sense, wikipedia says the C3 on indole is 10^13 times more reactive than benzene.