Difluoro borane

Bach, T., Lobel, J. Selective Prins reaction of styrenes and formaldehyde catalyzed by 2,6-di-tert-butylphenoxy(difluoro)borane. Synthesis... 

This reaction has been extended to the reaction between aldehydes and alkenyl complexes of boranes, silanes, and stannes to give allylic alcohols, " where the reaction with alkenyl complexes of silanes is known as the silyl-Prins reaction. In addition, several Lewis acids-mediated or -promoted Prins reactions have recently been developed, including the application of TMSI, hafnium (IV) bis(perfluorooctanesulfonyl)amides (in fluorous biphase system),iron (III) species," and 2,6-di-f rf-butylphenoxy(difluoro)borane. J... 

Dazard and Mongeot separated boron trifluoride from difluoro-borane by gas chromatography at low temperature. The column used was 50% Kel-F of a Chromosorb W at -196°C. Hydrogen was used as carrier gas,... 

Bach, T., Ldbel, J. (2002). Selective Prins Reaction of Styrenes and Formaldehyde Catalyzed by 2,6-Di-tert-butylphenoxy (difluoro) borane. Synthesis 172521-2526. 

The milder metal hydnde reagents are also used in stereoselective reductions Inclusion complexes of amine-borane reagent with cyclodexnins reduce ketones to opucally active alcohols, sometimes in modest enantiomeric excess [59] (equation 48). Diisobutylaluminum hydride modified by zmc bromide-MMA. A -tetra-methylethylenediamme (TMEDA) reduces a,a-difluoro-[i-hydroxy ketones to give predominantly erythro-2,2-difluoro-l,3-diols [60] (equation 49). The three isomers are formed on reduction with aluminum isopropoxide... 

To PhBCl2 (2 g, 13 mmol) in a 50-mL round-bottomed flask equipped with a short Vigreux column and a distillation head was added NaBF4 (3 g, 28 mmol) and the mixture was heated until the product distilled. The distillate [difluoro(phenyl)borane] distilled at 78 JC under atmospheric pressure. 

Difluoro-l-(tosyloxy)vinyllithium 586 has been employed as an acyl anion equivalent of the type 587. This anion was prepared by treatment of 2,2,2-trifluoroethyl tosylate with two equiv of LDA at —78 °C860 (Scheme 159). The reaction of intermediate 586 with carbonyl compounds, followed by acid hydrolysis, gave compounds 588 which, after basic treatment with sodium hydroxide, afforded ct-keto acids 589. The reaction of the intermediate 586 with boranes provided the corresponding borates, which have been used in the synthesis of fluorinated molecules861. 

The synthesis of the fluoroketone that combines the retroamide type bond (76) is shown in Scheme 5. The 2,2-difluoro-3-hydroxyester 11 from a Reformatsky reaction was converted to the primary amide 12 by treatment with ammonia in diethyl ether. Reduction of the amide with borane dimethyl sulfide and protection of the resulting amine gave the protected intermediate 13. For the preparation of peptides XIV and XV, the hydroxy function was oxidized to the corresponding ketone using pyridinium dichromate. 

Difluoro(dilluorophosphinoamino)borane has been prepared as shown in... 

BF2H6NS12 7V-(Difluoroboryl)disilazane Difluoro(A, A-disilylamino)borane (Difluoroboryl)disilylamine ... 

Following these observations, the influence of various borane-derived Lewis acids was probed by Yoshimura and co-workers [28]. Triethylborane exhibited no beneficial effect and difluoro(phenyl)borane was found to have a weaker catalytic activity than acetic acid. However, boron trifluoride and ethoxy diflu-oroborane showed stronger catalytic effects than acetic acid in the initial stage... 

Torres JC, Garden SJ, Pinto AC, da Silva FSQ, Boechat N (1999) A synthesis of3-fluoroindoles and 3,3-difluoroindolines by reduction of 3,3-difluoro-2-oxindoles using a borane tetrahydro-furan complex. Tetrahedron 55 1881-1892... 

Lebedev, V. N., Balagurova, E. V., Polyakov, A. V. et al. 1990. Selective fluorination of o- and m-carboranes. Synthesis of 9-monofluoro-, 9,12-difluoro-l,8,9,12-trifluoro-, and 8,9,10,12-tetrafluoro-o-carboranes and 9-monofluoro-, and 9,10-difluoro-m-carboranes. Molecular structure of 8,9,10,12-tetrafluoro-o-car-borane. J. Organomet. Chem., 385, 307-18. 

---