Normally, when carrying out a new reaction, it's good practice to do a small scale test reaction first to see if it'll work or not. But in a fit of madness I went against the convention by going in with all or nothing. After all, fortune is supposed to favour the brave, right?
The reaction in question: the Sonogashira a.k.a Sonogash, a classic textbook metal cross coupling reaction done neat with PdCl2(PPh3)4, Cu(I)I and NEt3. In lectures, we learned about the mechanisms of the catalytic cycle, but what we didn't cover was how this reaction was done experimentally.
Does it need to be anhydrous? was my first question, and a quick search online indicated that yes, this reaction is typically done under anhydrous and anaerobic conditions but that recently conditions had been developed in which this was not so important. Err, more detail please?
A Reaxys search for various preps didn't really help either, and since my NEt3 was more than likely to be wet, I decided to just chuck it all into the RBF, Argon the hell out of it anyway and pray to the gods of chemistry. A deep burgundy colour indicated that perhaps my prayers had been answered, but then I freaked out a little (a lot) when my reaction went black. No one had prepared me for this!
Later, I found out that It Was Fine, that in this case, black was good.
Looks like my copper got oxidised to Cu(II), and I don't know why!
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