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Halogen compoundsHalogen compounds Q 0090 Phenyl Trifluorovinyl Sulfide: A Radical Acceptor for Preparation of gem-Difluoromethylene Compounds. -The synthesis of the new radical acceptor (III), its oxidation to (IV), reaction with alkyl radicals and oxidation with subsequent Pummerer reaction of the radical adducts are reported. -(OKANO*, T.; CHOKAI, M.; HIRAISHI, M.; YOSHIZAWA, M.; KUSUKAWA, T.; FUJITA, M.; Tetrahedron 60

Reaction of 5-(Trifluoromethyl)-2(5H)-furanone under Basic Conditions: Stereo-Controlled Michael Dimerization.-Reaction of title furanone (I) with several bases affords the corresponding dimers (II) and (III) as a mixture of two of the four possible diastereomers. The product ratio depends on the basicity of the reaction medium. Thus, the kinetically controlled product (II) predominates in the presence of weak bases like DBU or Li 2 CO 3 , while the more stable isomer (III) is mainly formed under more basic conditions. The butenolide anion formed from (I) and LDA is stable and reacts as a Michael donor with various enones to give the corresponding Michael adducts (V) and (VII). -(OKANO, TAKASHI; CHOKAI, MASAYUKI; EGUCHI, SHOJI; HAYAKAWA, YOSHIO; Tetrahedron 56 (2000) 34, 6219-6222; Dep. Appl.