How do you make and use a Grignard reagent? This isn’t a question that has generally kept me awake at night. But last night it gave me nightmares. As a rule my ‘exam anxiety’ dreams, three decades after the event, feature maths: I find, days before the exam, that I have done none of the coursework or required reading, and am clueless about all of the mathematical methods on which I’m about to be grilled. Now it seems I may be about to transfer my disturbance to organic synthesis. Last night I was even at the stage of sitting in the exam hall waiting to be told to open the test paper, when I realised that I could recall not one of the countless details of reagents, methods and strategies involved in the Grignard reaction in particular (yes, alkylmagnesium, I know that much) or the aldol reaction, Claesen rerrangement, Friedel-Crafts acylation and all the rest. Now, I know this is nothing shameful even for someone who writes about chemistry for a living – as I say, it was three decades ago that I learnt this stuff, and if I want to know the details now then I can look them up, right? And my memory of the Diels-Alder reaction, about which I’ve written relatively recently, remains sufficiently fleshed-out to reassure me that the decay constant of my mind is at least still measured in years rather than days. All the same, it is sobering bordering on scary to realise that (i) I did once have to memorize all this stuff, and (ii) I did so. Organic synthesis can achieve tremendous elegance, and is not devoid of general principles; but this dream reminds me that it is nonetheless perhaps the closest chemistry comes to becoming a list of bald, unforgiving facts.
Oh God, and the truly scary thing is that I just looked up Grignard reagents on Wikipedia, and… and there was a carbonyl group lurking in my dream too. I think I’d have been more reassured to know that I was just improvising than that a fragment of that grim scheme has stayed lodged in my cortex.