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BOSS XI: Day 2   

24 July 2008 4,815 views 6 Comments

A few more highlights – this time from day 2 of the BOSS conference.

Masakatsu Shibasaki gave a real tour d’force, covering a hugely diverse range of reactions with an astounding array of reagents.  The Shibasaki chemical inventory must give the Corey labs a run for their money…

First-up was a bit of asymmetric epoxidation.  Shibasaki’s approach is quite different to that used by Yian Shi – rather than attempting an asymmetric oxidation, he’s targeted a asymmetric methylation of a carbonyl group, using the Corey-Chaykovsky reagent and the mother of all catalysts… (In case you’re wondering, that bad-boy weighs in at 1012 mass units)

The yields and enatioselectivities are generally excellent, but the range of substrates shown was somewhat limited – mostly aryl, but some alkyl.  This methodology nicely complements that of Shi, as the fructose based system is pretty poor when applied to terminal olefins.  Looks like Shibasaki’s running with this one though…

Next he showed us a bit of asymmetric conjugate addition of cyanide to enones.  Again, interesting catalytic system, but the group has a bit of history with this particular ligand.  In this case, the substrate screen was more extensive, showing both good yields and enantioselectivities.  However, there wasn’t much information about reactions in which R2 isn’t H.

Michael Crimmins didn’t give us too much in the way of methodology – a little more on the Ti-mediated aldol he’s been developing for a few years (which is an amazingly simple reaction to do – even I managed it). He showed the extension to glycolate aldols, and their use in total synthesis with a few Laurencia targets, including laurencin itself and obtusenyn. But the show piece was his synthesis of Brevetoxin… my jaw still gapes…

More tomorrow – Hartwig and Denmark…

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6 Comments

  • excimer says:

    I admire your liveblogging skills. What with the putting in pictures and all. I should have done that, but I’m lazy. My hat’s off to you.

  • TWYI says:

    Not live, the conference was last week…

  • Phil says:

    Shibasaki’s reagent does look quite big on paper. On the other hand, ol’ tetrakis-palladium has a MW of 1155…

    Have you heard KCN’s talk on Maitotoxin? Unlike Crimmins, he only gave a general overview of the chemical transformations used and didn’t go into detail afterwards, which made it harder to follow.

  • Alex says:

    Very interesting the asymmetric conjugate addition of cyanide to enones catalyzed by Gd(OiPr)3 even if the ee is not excellent (70%)…

  • InfMP says:

    maaan i wish i could see KCN, that would be awesome

  • GiVi says:

    he is lame and pretentious. his talk i saw was very superficial and mostly self-celebrating.