title: Reactions of β-alkoxyvinyl polyfluoroalkyl ketones with ethyl isocyanoacetate and its use for the synthesis of new polyfluoroalkyl pyrroles and pyrrolidines.
abstract: The hitherto unreported reactions of β-alkoxyvinyl polyfluoroalkyl ketones with ethyl isocyanoacetate and equimolar amounts of potassium-tert-butoxide proceeded mainly in the β-position of the α,β-unsaturated ketones in cases of α-nonsubstituted 1a–e and α-methyl substituted ketones 1g–j. Other α- or β-substituted ketones 1f,k–o gave mainly products 4 of initial attack at the carbonyl carbon. Depending on the solvent, the major products of β-attack do exist in different tautomeric forms. Generally the openchain enol tautomers 5 predominate in the polar DMSO-d(6), while the cyclic γ-hemiaminals 8 are the major tautomers in the less polar CDCl(3). Acid treatment of the latter compounds 8 led to the hitherto unknown ethyl 5-polyfluoroalkyl-pyrrole-2-carboxylates 11 by elimination of formic acid. Catalytic hydrogenation of pyrrole 11a was used for the synthesis of earlier unknown 5-trifluoromethyl proline 16.
authors.affiliation: Institute of Bioorganic Chemistry and Petrochemistry, National Ukrainian Academy of Sciences, Murmanska 1, Kiev-94, 02660, Ukraine.
authors.forename: Ivan S
authors.initials: IS
authors.lastname: Kondratov
authors.forename: Violetta G
authors.initials: VG
authors.lastname: Dolovanyuk
authors.forename: Nataliya A
authors.initials: NA
authors.lastname: Tolmachova
authors.forename: Igor I
authors.initials: II
authors.lastname: Gerus
authors.forename: Klaus
authors.initials: K
authors.lastname: Bergander
authors.forename: Roland
authors.initials: R
authors.lastname: Fröhlich
authors.forename: Günter
authors.initials: G
authors.lastname: Haufe
mesh_terms: D000085:Acetates / Q000138:chemical synthesis / Q000737:chemistry*; D002384:Catalysis; D006865:Hydrogenation; D007659:Ketones / Q000138:chemical synthesis / Q000737:chemistry*; D008958:Models, Molecular; D011758:Pyrroles / Q000138:chemical synthesis* / Q000737:chemistry; D011759:Pyrrolidines / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: D000085:Acetates; D007659:Ketones; D011758:Pyrroles; D011759:Pyrrolidines