[jeffwm]

Hello all,

I have been trying do a reaction that published very high yields and great reproducibility for quite some time now. It involves reacting ethyl indole-2-carboxylate with 3-formylpyridine. The conditions are supposed to be in ethanol @RT for 8hrs with TMG (1,1,3,3-tetramethylguanidine). It's supposed to be a very simple reaction that couples the two SM at the 3 position of the indole, making an alcohol where the aldehyde once was.

I have taken NMR of both the indole and aldehyde SM and they are textbook clean. My ethanol is stilled freshly. But for some reason, I only get starting materials on TLC. I have done the following to troubleshoot:

let react for up to 36 hrs @RT, gentle heatings of 50C for up to 36hrs, refluxed for up to 36 hrs, add excess TMG, make the indole excess, make the aldehyde excess, varied the solvent with 4 others

yet I still only get the starting material for this simple reaction.

I was wondering if anyone had any suggestions/has used TMG before themselves and also had an issue with it performing properly. My TMG is less than a year old and is stored under nitrogen in our lab's fridge wrapped with parafilm.

Thanks in advance for any help/suggestions, it's greatly appreciated

[clarkstill]

I'm not sure what the precedent is that you're citing, the only hit in reaxys for these two reagents is given below. Is it a very recent paper? Otherwise I'm not sure whether the precedent really exists.

[willug]

I think TMG forms a forms a complex with CO2, so it's worth distilling before use (from CaH2 say). Is yours yellow/orange? If so, that might be worth a go. I've used it for HWE reactions before, and had trouble getting those to go before I did that...