| Abstract
| - The chemoselectivity of activation by a (PPh3)4Pd catalyst on a series of small, olefin-basedcompounds that were substituted with a variety of allylic and vinylic functional groups was studied. Ofparticular note, the allylic acetate of 1-acetoxy-2-bromo-2-propene (7) was selectively ionized by Pd in thepresence of a malonate nucleophile, while oxidative addition of the C−Br bond to Pd occurred exclusivelyin the presence of a boronic acid nucleophile. When the acetate nucleophile was used, no ionization of theacetate leaving group occurred at all, which was proven by the use of deuterium-labeled substrates (e.g.,11). This report demonstrates that the nucleophile interacts in some way with Pd prior to catalyst activationof the substrate. Certainly in the case of the malonate nucleophile, this is without precedent and contradictsthe central dogma of how these proposed catalytic cycles operate.
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