So this is the general procedure I decided upon:
Indole-3-acetic acid (1 eq.) was dissolved in DCM and to this was added a very small amount of DMF and oxalyl chloride (5 eq.) – the reaction was kept under nitrogen and was allowed to proceed at 0 degC for 2 hours, after which time both the DCM and oxalyl chloride were removed under reduced pressure.
In the meantime, Indole (1 eq.) was dissolved in DCM and to this was added aluminium trichloride (2 eq). The resulting brown slurry was allowed to stir under nitrogen at 0 degC for 30 mins before a solution of the previously prepared acyl chloride (1.5 eq) was slowly added dropwise to it. The mixture went from brown to a deep black and effervescence was noted. The reaction was then allowed to stir vigorously at RT overnight before being quenched with MeOH, poured over ice, extracted with DCM and the combined DCM extracts being washed with saturated aqueous sodium bicarb, brine and dried before being concentrated to give a dark red solid.
I checked the crude product by TLC and there are two spots and then considerable streaking. Comparing the crude spot with indole and indole-3-acetic acid I can see that the top spot corresponds to indole. There's a possibility that the next spot corresponds to the indole-3-acetic acid methyl ester after the methanol quench.
I'm going to column the crude material later to isolate enough of the second spot in order to NMR it! I'll return soon with more updates