National Organic Symposium. Tuesday Morning.

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Bad day for Th’ Gaussling to be away. The hounds are snapping at my heels at work.

I managed only to see Eric Jacobsen‘s talk on catalytic urea chemistry. Jacobsen’s system is pretty much a chiral proton ligand that can carry along a nucleophilic counter anion. Configured differently, urea’s and thiourea’s with BARF groups on the nitrogen can coordinate with chloride. This can lead to the abstraction of chloride to give a carbenium ion that can then participate in a enantioselective Pictet-Spengler type reaction. 

Jacobsen’s system resembles a radically stripped down enzyme in terms of 3-point binding interactions by hydrogen bonding.  Where Jacobsen went askew is the use of calculations to justify his mechanistic model. The models did not include solvent interactions when affording only 0-2 kcal/mol (!!) differences in energy. Naturally this did not set well with certain distinguished members of the Audience.  The ΔΔG’s did not correlate with the ee’s at all either.

A certain J.D. Roberts took great exception to Jacobsen’s molecular modeling results, resulting in the spectacle of a Harvard Professor frantically qualifying his slides and words as he back pedalled for all he was worth. There was some actual contrition there on the stage. It was quite a thing to see. There but for the grace of God go I.

6 thoughts on “National Organic Symposium. Tuesday Morning.”

  1. Jordan

    I once saw a fairly well-known Harvard materials guy seriously humbled on the podium at a Gordon Conference. He had parachuted in for the last talk of the conference, put up a bunch of cool results, then got called out on his conclusions one-by-one by members of the audience. It was quite a sight.

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  2. Chemgeek

    You forgot to mention that Streitweiser got the microphone next and said, “I’m Streitweiser. That was a good answer.”

    I didn’t get the same impression that you did that Jacobsen got taken to the proverbial woodshed by Roberts. Although he made some valid points, Jacobsen handled it pretty well.

    Sadly, the NOS just doesn’t have the right atmosphere for a full blown, drag out fight.

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    1. gaussling Post author

      I did hear the comment by Streitweiser. Friendly as it was, it didn’t really help Jacobsen’s case that much. Eric should have left the calculations out of the talk. The system is just too complex to expect reliable output. That being said, it is a good project and anyone doing mechanistic work these days should be encouraged.

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