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Facile Preparation of (2Z,4E)-Dienamides by the Olefination of Electron-deficient Alkenes with Allyl Acetate
Published on: June 21, 2017
Lewis acid-promoted Friedel-Crafts alkylation reactions with alpha-ketophosphate electrophiles
Austin G Smith1, Jeffrey S Johnson
1Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, USA.
Abstract:
The BF(3).OEt(2)-promoted nucleophilic substitution of alpha-aryl-alpha-ketophosphates to afford alpha,alpha-diaryl ketone products is described. Electron-rich alpha-ketophosphates perform best, with electron-neutral and electron-poor substrates also tolerated. The reaction is tolerant of a range of aromatic, heteroaromatic, and nonaromatic nucleophiles, with yields ranging from 44% to 84%. Enantioenriched starting material yields racemic product, suggesting an S(N)1 pathway via an acylcarbenium ion.
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