Efficient synthesis of perfluorinated tetracyclones

ORGN 155

Paul A. Deck, pdeck@vt.edu and Brian S. Hickory. Department of Chemistry, Virginia Tech, 107 Davidson Hall, Blacksburg, VA 24061-0212
Existing syntheses of perfluorotetracyclone (by cobalt-mediated cyclocarbonylation of the corresponding perfluorotolane, Dickson & Michel 1975) usually give mixtures of products. We have developed an alternative approach that offers significant improvements in generality and efficiency. We already showed (Organometallics 2001) that arylation of NaC5H5 with excess C6F6 and NaH gives chromatographically separable mixtures of C6F5-substituted cyclopentadienes. Forcing conditions give the tetraarylated species exclusively in about 50% isolated yield. We have since extended this strategy to arylations using pentafluoropyridine and octafluorotoluene. Subsequent oxidation of the tri- and tetra-arylated cyclopentadienes affords the corresponding cyclopentadienones in high yield. This paper will describe our synthetic methods, the characterization of the product ketones, reactivity trends in the reactions of these ketones with terminal alkynes, and our efforts to use the latter reactions in the preparation of fluorinated polyarylenes.