- Vibrational studies of trans-stilbenes--II. Infrared and Raman spectra of fluorinated trans-stilbenes
-
Infrared and Raman spectra of trans-α-fluoro-stilbene, trans-α,α'-difluoro-stilbene, trans-4,4'-difluoro-stilbene and trans-2,2',3,3',4,4',5,5',6,6'-decafluoro-stilbene were recorded and are reported here for the first time.The assignments are proposed fo
- Meic, Z.,Guesten, H.
-
-
Read Online
- π-Stacking interactions in some crystalline cisoid E,E-1,4-diaryl-1,3-butadienes
-
A cisoid E,E-1,4-diperfluorophenyl-1,3-butadiene has been prepared in which offset stacking between perfluorophenyl-perfluorophenyl rings occurs, and face-to-face stacking between phenyl-perfluorophenyl rings is found in crystals of its 1:1 complex with a
- Liu, Jin,Murray, Elisia M.,Young Jr., Victor G.
-
-
Read Online
- Catalytic enantioselective allyl- and crotylboration of aldehydes using chiral diol·SnCl4 complexes. Optimization, substrate scope and mechanistic investigations
-
We report a novel class of C2-symmetric chiral diols derived from the hydrobenzoin skeleton. The combination of these diols with SnCl 4 under Yamamoto's concept of Lewis acid assisted Bronsted acidity (LBA catalysis) leads to high levels of asymmetric induction in the allylboration of aldehydes by commercially available allylboronic acid pinacol ester 1a. The corresponding homoallylic alcohol products of synthetically useful aliphatic aldehydes are obtained in excellent yields with up to 98:2 er. This combined acid manifold is also efficient in catalyzing the diastereo- and enantioselective crotylboration of aldehydes, thus providing the propionate units in >95:5 dr and up to 98:2 er. The X-ray crystal structure of the optimal diol·SnCl4 complex, Vivol (4m)·SnCl 4, unambiguously shows the Bronsted acidic character of this LBA catalyst and its highly dissymmetrical environment. Further controls have ruled out a possible boron transesterification mechanism with the chiral diol and point to LBA catalyst-derived activation of the pinacol allylic boronates 1. Due to slow dissociation of the diol·SnCl4 complex, a small excess of diol is required in order to suppress a competing racemic cycle catalyzed by free SnCl4.
- Rauniyar, Vivek,Zhai, Huimin,Hall, Dennis G.
-
supporting information; experimental part
p. 8481 - 8490
(2009/02/02)
-
- Pentafluorophenyl carbonyl compounds in the Reformatsky-type reactions promoted with Fe(CO)5-based metal complex systems
-
Iron pentacarbonyl is an effective promoter for additions of halogenated acid esters and nitriles to pentafluorophenyl carbonyl compounds 1, 4, and 5 by the Reformatsky-type reaction and reductive coupling of compound 1. The electron-withdrawing character
- Terent'ev,Vasil'eva,Chahovskaya,Mysova,Hambardzumyan,Kochetkov
-
p. 669 - 673
(2008/12/22)
-
- Diastereoselective synthesis of pinacols from aromatic aldehydes using the system pentacarbonyliron-hexamethylphosphoric triamide. Dual reactivity of pentafluorobenzaldehyde
-
The system Fe(CO)5-HMPA effectively promotes diastereoselective reductive dimerization of aromatic aldehydes to the corresponding pinacols having preferentially or exclusively dl configuration. In the reaction with pentafluorobenzaldehyde, the product structure strongly depends on the presence of traces of moisture in the reaction system. Nauka/Interperiodica 2007.
- Terent'ev,Vasil'eva,Chakhovskaya,Mysova,Kochetkov
-
p. 518 - 521
(2008/02/02)
-
- Phenyl-perfluorophenyl stacking interactions: Topochemical [2+2] photodimerization and photopolymerization of olefinic compounds
-
The face-to-face stacking interaction between phenyl and perfluorophenyl groups is emerging as a common noncovalent interaction. To explore the generality of this supramolecular synthon, the solid-state packing structure and reactivity of several monoolefins and diolefins substituted with phenyl and perfluorophenyl groups was investigated. Of the seven crystalline or cocrystalline materials investigated, six were found to undergo a photochemically induced [2+2] reaction in the solid state. By determining the stereochemistry of the photoproduct and/or X-ray structural analysis of the olefinic precursors, the stacked interaction between phenyl and perfluorophenyl groups in the photoactive crystals were revealed.
- Coates, Geoffrey W.,Dunn, Alex R.,Henling, Lawrence M.,Ziller, Joseph W.,Lobkovsky, Emil B.,Grubbs, Robert H.
-
p. 3641 - 3649
(2007/10/03)
-
- OLIGOMERIC POLYPARATETRAFLUOROPHENYLENE VINYLENES: A NEW SYNTHESIS BASED ON THE NUCLEOPHILIC SUBSTITUTION OF THE PARA FLUORINE DURING THE REACTION OF (E)-2-(PENTAFLUOROPHENYL)ETHENYL LITHIUM WITH HEXAFLUOROBENZENE
-
(E)-2-(Pentafluorophenyl)ethenyl bromide (3) has been prepared by three routes: (i) bromination of 2,3,4,5,6-pentafluorocinnamic acid (5) gave 1,2-dibromo-2-(pentafluorophenyl)propionic acid (6) which was converted into 1,1,2-tribromo-2-(pentafluorophenyl
- Brooke, Gerald M.,Mawson, Simon D.
-
p. 111 - 122
(2007/10/02)
-