I came from Hong Kong about a week ago, where I gave a talk at the Hong Kong Institute of Science and Technology (HKUST). During this trip, Professor Jianwei Sun was my host and he managed to put together a superb visit. It is too bad that I was not able to stay longer: due to my teaching commitments I ended up going 12 times zones away for only 3 days. As usual, I got exposed to some really inspiring science. In the past, I mentioned Jianwei’s imaginative research, so today I want to talk about a paper from one of his colleagues, Professor Rongbiao Tong. I was really interested to hear about his approach to the cephalosporamide family of natural products. To me, the coolest aspect of Tong’s method lies in his handling of phenol’s aromatic framework. Below I am summarizing the key transformations of the phenol skeleton in Tong’s synthesis. The sequence starts by dearomatization with PhI(OAc)2, followed by desilylation. If you track the rest of the steps in Tong’s Org. Lett. paper, you will learn how tosic acid-promoted oxa-Michael cyclization ultimately leads to the formation of the tricyclic ether core indicated below. It is fun to think about the origins of the blue string of carbon atoms in the product. The fact that all of them originate from the aromatic scaffold of a para-substituted phenol derivative is pretty remarkable.
amphoteros 