Yay, I did live to see it! The very reaction I requested here, a little more than a year ago. Check out this fantastico, shmantastico cross-coupling, in the latest issue of the best journal on Earth:


Org. Lett. 2012, ASAP (DOI: 10.1021/ol3029109)

Do you see what I see? I see:

  • A straight TMS-arene in a palladium catalyzed cross coupling — FINALLY!
  • C-H activation. Always nice. More of that, thank you.
  • Selectivity for the beta-position of thiophenes. (Rare shit, trust me.)
  • R = everything. Cool.
  • No weird catalysts or ligands. Huge plus.

…and I haven’t even read the paper yet :)

This from the graphical abstract. Now I know what to read tonight.

 

3 Responses to A God-sent cross-coupling

  1. milkshake says:

    the used catalyst PdCl2.2MeCN is as simple and cheap as it gets. Dont waste money on buying it – instead buy the cheapest (dubious purity) grade of anhydrous PdCl2, powder it, suspend it in a large volume of a good grade acetonitrile (does not need to be anhydrous) and reflux for about 20 minutes, filter while hot and then let the obtained yellow solution sit overnight undisturbed. PdCl2.2MeCN has limited solubility in cold MeCN and crystallizes out as a yellow bench-stable solid. A second batch is obtained by concentrating the supernatants on rotovap. The yield is about 80-90% theory

    Please note that PdCl2.2MeCN acts like a fairly strong Lewis and Bronstead acid and sensitive groups like TBS, TES and MOM can get cleaved. In hot acetonitrile it catalyzes dehydratation of primary amides to nitriles

  2. Karl Collins says:

    They just need the selectivity….

  3. drfreddy says:

    Great read indeed, despite a decent rationale for the peculiar beta-selectivity. If this works for other groups, this paper is gonna be cited like hell.

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