- Process for producing 1,1-Difluorovinyl cycloaliphatic compounds
-
This invention relates to a process for the preparation of 1,1-difluoroolefins, e.g., difluorovinyl cycloaliphatic compounds such as difluorovinylcyclohexane and derivatives by the dehydrofluorination of a trifluoromethyl-substituted cycloaliphatic compou
- -
-
Page/Page column 4
(2008/06/13)
-
- Transformation of Carbonyl Compounds into gem-Difluoro Compounds with Dibromodifluoromethane/Zinc Reagent
-
Reaction of carbonyl compounds with dibromodifluoromethane/zinc gives the gem-difluoro compounds (12 examples).It seems to be that the reaction involves the generation of difluorocarbene by reaction of dibromodifluoromethane with zinc, followed by product
- Hu, Chang-Ming,Qing, Feng-Ling,Shen, Cun-Xi
-
p. 335 - 338
(2007/10/02)
-
- Fluorination of Unsaturated Aldehydes with Sulfur Tetrafluoride
-
Fluorination of unsaturated aldehydes 1 with SF4 in the presence of KF at 20 deg C leads to the corresponding difluoromethyl-substituted compounds 2 in various yields.Dehydrohalogenation of 1-bromo-1-(difluoromethyl)- (2b) or 1-bromo-1-(trifluoromethyl)cy
- Haas, Alois,Pluemer, Rita,Schiller, Achim
-
p. 3004 - 3010
(2007/10/02)
-
- Ylide-Carbene Chemistry. Synthesis of 1,1-Difluoro-1-alkenes
-
The reaction between nonstabilized alkylidenetriphenylphosphoranes and chlorodifluoromethane has been found to be a useful alternative to the Wittig reaction for the synthesis of many difluoromethylene olefins.Both primary and secondary ylides which do not contain strongly electron-withdrawing substituents within the alkylidene portion of the ylide react with chlorodifluoromethane to give the corresponding difluoromethylene olefins in yields which are significantly better than those obtained by the Wittig reaction.The formation of triphenylphosphine oxide is avoided, and all phosphorus-containing moieties can be recovered and recycled.The reaction proceeds by initial dehydrochlorination of chlorodifluoromethane by the ylide to generate difluorocarbene.The intermediate difluorocarbene is then trapped by a second equivalent of the nucleophilic ylide.Mechanistic evidence indicates that either a zwitterionic intermediate or a three-membered cyclic phosphorane can account for the 1,1-difluoro-1-alkene products.The isolation of several 1-hydro-1-fluoro-1-alkene products such as FCH=CHPh, FHC=CPh2, and FHC=CHCH=CHPh after steam distillation of the reaction mixtures, however, can only be accounted for via a three-membered cyclic phosphorane.
- Wheaton, Gregory A.,Burton, Donald J.
-
p. 917 - 927
(2007/10/02)
-
- PREPARATION AND SYNTHETIC UTILITY OF FLUORINATED PHOSPHONIUM SALTS, BISPHOSPHONIUM SALTS AND PHOSPHORANIUM SALTS
-
The reaction of tertiary phosphines with fluorohalomethanes provides a rapid and high yield synthesis of various types of fluorinated phosphonium salts, bis-phosphonium salts and phosphoranium salts.These salts are useful precursors to fluorine-containing
- Burton, Donald J.
-
p. 339 - 358
(2007/10/02)
-
- THE PHOTOELECTRON SPECTRA OF 4-METHYLENE THIACYCLOHEXANE DERIVATIVES THROUGH-BOND INTERACTION
-
The photoelectron spectra of 4-methylene thiacyclohexane, 4-difluoromethylene thiacyclohexane and trans-2-methylene-6-thiaperhydronaphthalene are described and compared with thiacyclohexane, difluoromethylene-cyclohexane and cis-2-methylene-6-thiaperhydronaphthalene.A through bond interaction between the sulphur lone pair and the vinyl-?-system is observed.The results are discussed in relation with the sigma-coupled transition observed in the electronic absorption spectra of the dicyano methylene derivatives by P.Pasman.
- Sarneel, R.,Worell, C. W.,Pasman, P.,Verhoeven, J. W.,Mes, G. F.
-
p. 3241 - 3248
(2007/10/02)
-