This past Monday night I flew into Indianapolis, where Prof. Mark Lipton met me at the airport and took me to West Lafayette, home of Purdue University. Mark organized this trip for me, and I am truly grateful for it because I got to see people whose work I have known and admired for a long time. I also got to meet new faculty members, whose science I discovered only recently. I previously blogged about some nice chemistry coming out of Prof. Mingjie Dai’s lab. This time around I also met Chris Uyeda, another Assistant Professor at the Chemistry Department, whose cool catalysis will undoubtedly grace the pages of a top-level chemistry journal some time soon (he has a great story to tell, and it is too bad that I cannot mention any details as this is still unpublished…).
There were some really interesting science vignettes I was exposed to and there was a theme to my visit: I kept getting pleasantly surprised while learning about methods I had known very little about. Take, for instance, a very nice paper by Prof. Alex Wei. In it, an attempt is made to rationalize the remarkably high level of relative stereochemistry observed in the following epoxidation:
This system was subjected to a thorough DFT analysis, but neither of the two diastereomeric transition states revealed specific enthalpic interactions that could account for the observed differentiation. Upon further analysis, the authors came to the conclusion that the early transition state and low activation energy might allow for an intrinsic polarization in pi-orbital reactivity. They employed PPFMO (Polarized-pi Frontier Molecular Orbitals) approach, which is a perturbation method that desymmetrizes 2p orbitals by introducing s-functions near each lobe… This method provides an important clue that suggests that facial selectivity is predetermined by the polarized-pi model. Very interesting stuff, in my view.
There is another notable rarity I got exposed to. If you are aware of the USA map, you would know that West Lafayette, Indiana, is not exactly the place where one would expect to find good sushi. However, I was amazed by the quality of food at the Heisei restaurant, Professor Negishi’s favorite place. Mark took me there last night, along with Mingjie and Chris. Apparently, there is a good explanation for the outstanding quality of fish: there is a Subaru plant nearby. Their management wanted to make sure that Subaru employees had access to top of the line sushi. Apparently, Prof. Negishi ordered a take-out from that place on the day he received his Nobel Prize in 2010…
P. S. There was another surprise today: one of my readers alerted me that there are some weird ads that appear next to my posts from time to time. Upon further digging, I realized that I have to pay extra so that my readers do not see this stuff (by the way, as the writer of this blog, I never see any ads). This was a rather unpleasant surprise, the one I just fixed by paying a significantly higher annual fee. Let me know if you still see those stupid things. I will kick someone’s teeth in at WordPress if I hear about these ads again. The gospel of science must be spread without commercial interruptions.
10:1 selectivity is not that startling, for a reaction with highly organized transition state, run at -55C. Even a very tiny difference in the activation energy will have huge effect on ratio, at low temperature.
Also, people who use DMDO sometimes complain about the low concentration of the reagent (typically 0.06-0.07M) which limits the utility on multi-gram scale, whereas for the (more reactive) fluorinated version of DMDO the cost of trifluoroacetone becomes the limiting factor on scale. They don’t realize that dioxirane derived from cheap methyl ethyl ketone has similar properties to DMDO, and can be easily obtained in more concentrated solutions (0.12M)
Yes – but the “majority rule” hinted at by the authors is very interesting…