Xenon-boron bonds

Alkenes react with xenon difluoride in the presence of some auxiliary reagent to form unsymmetrical addition products. Treatment of indene (8) with xenon difluoridc and methanol in the presence of hydrogen fluoride leads to fluoromethoxylation of the C = C bond, dia-stereomers of 1-alkoxy-2-fluoroindane are formed as the major product, difluoroindane was detected in trace quantities. In the presence of a boron trifluoride-diethyl ether complex the crossover l-fluoro-2-alkoxylated indanes have been obtained as major products.48,49... 

In 1989 the synthesis and isolation of the first compounds with stable Xe—C bond were reported by Naumann and Tyrra285 and Frohn and Jakobs1068 by the introduction of the organic group through nucleophilic substitution called xenodeborylation [Eq. (4.256)]. The boron as Lewis acid center polarizes the Xe—F bond and thereby allows it to overcome the low electrophilicity of the Xe center to form the fluoroar-ylxenonium fluoroborates 366. When the reaction is carried out in anhydrous HF, all C6F5 groups of the borane are transferred to xenon [Eq. (4.256)].1069... 

Korytnyk and coworkers have shown that reactions of xenon difluoride with acetylated glycals in the presence of boron trifluoride are a convenient route for the synthesis of 1,2-difluoro sugars, while the addition of fluorine to the double bond occurred predominantly from the less hindered side and cis adducts were mainly formed75, 76. Stereoselective transformation of tri-O-acetyl-D-galactal with xenon difluoride at -20 to +5 °C, without a catalyst in CFC13, after hydrolysis, afforded 2-deoxy-2-fluoro-D-galactose in 63% yield77. 

Nelson and Gordy (7) were successful in producing trapped BFg radicals by gamma irradiation of solid xenon which contained small concentrations of BFg. From observations on the electron-spln-resonance spectra of these radicals, a bond angle of 112 for BFg was derived by these workers to account for the hybridization of the o-bondlng orbitals of the boron atom. We adopt their... 

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