74492-30-1Relevant articles and documents
Facile synthesis of unsymmetrical 1,1-diaryl-2,2-difluoroethenes via stepwise coupling of 1,1-dibromo-2,2-difluoroethenes
Fujita, Takeshi,Suzuki, Naoto,Ichitsuka, Tomohiro,Ichikawa, Junji
, p. 97 - 101 (2013/10/01)
Unsymmetrical 1,1-diaryl-2,2-difluoroethenes were synthesized from 1,1-dibromo-2,2-difluoroethene, which is commercially available, via the Suzuki-Miyaura coupling in a stepwise fashion. Suitable ligands for each coupling process were used to achieve selective synthesis of these diaryldifluoroethenes.
A New Route for the Preparation of Substituted 2,2-Difluorostyrenes and a Convenient Route to Substituted (2,2,2-Trifluoroethyl)benzenes
Nguyen, Ba V.,Burton, Donald J.
, p. 7758 - 7764 (2007/10/03)
The (2,2-difluoroethenyl)zinc reagent II is coupled with aryl iodides or bromides in the presence of Pd(PPh3)4 in DMF to give the corresponding 2,2-difluorostyrenes IV. The 4-substituted (tetrafluoroaryl)copper reagents are coupled with 2,2-difluoro-1-iodoethylene (I) to produce the corresponding styrene derivatives VII. Both methods provide good yields of the coupled products. These products react with wet KF in DMF or DMSO to form the (2,2,2-trifluoroethyl)benzene derivatives VIII in good yields.
Use of Kinetic Isotope Effects in Mechanism Studies. 4. Chlorine Isotope Effects Associated with Alkoxide-Promoted Dehydrochlorination Reactions
Koch, Heinz F.,McLennan, Duncan J.,Koch, Judith G.,Tumas, William,Dobson, Brian,Koch, Nanci H.
, p. 1930 - 1937 (2007/10/02)
The method of measuring k35/k37 for the alkoxide-promoted deprotiochlorination and dedeuteriochlorination reactions has been applied to C6H5CiH(CH3)CH2Cl (I-Cl), C6H5CiHClCH2Cl (V), and C6H5CiHClCF2Cl(III).For reactions occuring with ethanolic sodium ethoxide the following values for k35/k37 have been measured: I-Cl-h, 1.00590 + 0.00013, and I-Cl-d, 1.00507 +/- 0.00036 at 75 deg C; V-h, 1.00908 +/- 0.00008, and V-d, 1.00734 +/- 0.00012 at 24 deg C; III-h, 1.01229 +/- 0.00047, and III-d, 1.01003 +/- 0.00024 at 0 deg C.Methanolic sodium methoxide promoted eliminations gave similar results for V and III: V-h, 1.00978 +/- 0.00020, and V-d, 1.00776 +/- 0.00020 at 21 deg C; III-h, 1.01255 +/- 0.00048, and III-d, 1.01025 +/- 0.00043 at 20 deg C.The results for I-Cl are most consistent with an E2 mechanism, while the results for III and V suggest a multistep reaction sequence.The Arrhenius behavior of ethoxide-promoted dehydrochlorination of V-h gives a good linear correlation between -10 and 50 deg C, with an EaH = 21.26 +/- 0.05 kcal/mol and ln AH = 29.29 +/- 0.09.Rate constants measured for 55, 60, 65, and 70 deg C show increasing negative deviation from the slope.Similar behavior was not observed for V-d which resulted in EaD = 21.57 +/- 0.28 and ln AD = 28.37 +/- 0.28 when rate constants over a 50 deg C range (20 - 70 deg C) were used.The ΔEaD-H = 0.31 and AH/AD = 2.5 for an observed kH/kD = 4.24 at 25 deg C were similar for results obtained for III.The possibility that the high values of k35/k37 for both III and V could result from a chlorine isotope effect associated with the proton transfer step of an E1cB mechanism is discussed.
