Sorry things have been so quiet around here the last couple of weeks - I've been a bit uninspired, the start of term has been a bit hectic, and my boss has finally noticed that I haven't really made any progress in the last six months. Hopefully more things soon as I wrestle my life back under control.
A few weeks ago, as the result of a conversation in the lab, I thought it might be interesting to pick a popular molecule (i.e. something of which there have been numerous syntheses), and see how much better we've gotten at making it over time. After a bit of thought I settled on strychnine, and in order to not waste an excessive amount of my life, only took syntheses which produced a single enantiomer of the natural product. So, first let us look at how the number of steps (in the longest linear sequence) has varied over the years.
Right, so that's kind of as it should be - not the sharp downward trend one might have expected, but at least it's decreasing over time. Why, by 2110 we'll be making it in no steps at all! And it'll make a good undergraduate experiment in eighty years or so. Excited and thrilled by my predictive powers (and being a fairly cynical person) I thought it'd also be interesting to plot the average yield per step against year.
Huh, so it turns out that we're not really getting any better yields now than R. B. Woodward was half a century ago. And no perfect synthesis for a few thousand years, if present trends continue. Personally, I'd expected a much greater upward gradient for this graph, as we, err, become better chemists. Or something.
1. Probably. I failed AS maths.
2. I found synarchive.com to be a massive help in this exercise. Where yields were only available over 2 steps (or more; fairly common in the literature) then I've just counted the 2 steps as 1 with the yield given. I realise this is a very stupid thing to do, but this is not a serious post, and I can't think of a better way to fill in the gaps where the yield for each step separately simply isn't available. Also, average yields were worked out using my phone, while watching old episodes of Red Dwarf. So I wouldn't publish this data without checking it.