As much as I’ve enjoyed my forays into analytical and flavour chemistry, yesterday afternoon I had a relapse and attended the Arthur C. Cope session on organic chemistry in the cathedral-sized ballroom. Actually, the cathedral analogy doesn’t seem a bad one, as sometimes it does feel as if there’s a certain amount of worshipping going on.
I really enjoyed this session because it had an ecelectic mix of topics. Highlights for me included Kenneth Shea‘s talk on how to build polyethylene molecules from single-carbon units, in a living polymerization reaction involving ylides and diazoalkanes. In this way, he’s made some unusual polymers – such as chains with high steric congestion that can’t be prepared using traditional methods for polyolefin preparation.
I also liked Leonard MacGillivray’s presentation on solid-phase organic reactions. He co-crystallizes pairs of organic compounds to form lattices in which hydrogen-bonding aligns the molecules in a perfect orientation for reaction – specifically, photodimerization reactions between alkenes to form cyclobutanes. Because the lattice holds the molecules in very specific orientations, the stereochemistry of the process is precisely controlled.
But my favourites were Dave Macmillan and Andre Charette. Charette described his work on the preparation of chiral amines by adding organozinc reagents to N-phosphinoylimines. Now I’ve always been a bit dubious about dialkylzinc compounds, because they’re a pain to make. But Charette has thought of this, and has developed a relatively simple way to make them from zinc methoxide – so top marks for thinking of the practicalities.
MacMillan discussed his work on SOMO-activation reactions using organocatalysis. I liked the way that he gave much of the credit for this idea to his co-worker, Teresa Beeson. His group are currently developing new reactions using SOMO-activation, so expect to see enantioselective alpha-halogenation of aldehydes, vinylation reactions, and the enentioselective alkylation of cyclic ketones (which apparently requires a completely different catalyst to the one currently published).
All in all it was a top session. The only down-side was the way that people in the audience would get up and leave as soon as the speaker they were interested in had finished. I know that people have to focus on lectures in their own fields to get the most out of these meetings, but if they’d stuck around for the whole session I think they’d have found the variety of topics refreshing and stimulating.
Andrew Mitchinson (Associate editor, Nature)