Will a machine put synthetic organic chemists out of business. Is its proponent and inventor Martin Burke the anti-Christ? 2 years ago he thought that he’d need 5,000 building blocks to make 282,487 natural products. Now he’s down to 1,400, 20 years and 1 Billion dollars [ Science vol. 356 pp. 231 – 232 ’17 ].
Back in the day we studied the zillions of terpene natural products built from various machinations of just the isopentyl group. Does he really need another 1,399?
The synthesis is a modification of the Suzuki synthesis in which R-B(OH)2 and R’ – X are coupled by palladium to form R -R’. It uses MIDA (HOOC CH2 NCH3 CH2 COOH — N-MethylIminodiAcetic acid) which wraps itself around the boron and shuts down further synthesis.
In 2008 Burke found that MIDA boronates stick to silica when methanol and ether are both present, and then drop off when tetrahydrofuran (THF) is present. This allows catch and release. For purification they can run the compounds through a silica containing vial.
In 2015 some 200 building blocks with the halogen and MIDA capped boronic acid were availablle commercially.
Burke hooked up with a computer scientist to look at the structures of the 282,487 and break them down into fragments needing only carbon carbon bond formation — a fascinating problem in graph theory.
Derek did a post on this a few years ago. Hopefully he’ll do another.