6783-09-1Relevant articles and documents
Amino and Alkyl B-Substituted P-Stabilized Borenium Salts
Devillard, Marc,Bouhadir, Ghenwa,Mallet-Ladeira, Sonia,Miqueu, Karinne,Bourissou, Didier
, p. 3788 - 3794 (2016)
The ability of the phosphino-naphthyl moiety to stabilize amino- and alkylborenium cations has been studied. Surprisingly, the phosphine-aminochloroborane precursor 2 was found to exist in neutral open form (without PaB interaction) in benzene solution and in the solid state but to ionize spontaneously in chloroform to generate the P-stabilized borenium salt 3. Addition of gallium trichloride shifts the process forward and affords the corresponding tetrachlorogallate borenium salt 3′. The phosphine group of 2 remains available for external reactivity, as shown by the ready formation of the corresponding phosphine gold(I) chloride complex 4. The P-stabilized cyclohexylborenium cation 6 has also been prepared by reacting the corresponding bromoborane 5 with gallium tribromide. Compound 6 is a very rare example of an alkyl-substituted borenium salt. The structures of 2, 3′, and 4-6 have been unambiguously ascertained by multinuclear NMR spectroscopy and X-ray crystallography.
Organoboranes. 29. A convenient synthesis of alkyldibromoboranes and dialkylbromoboranes via hydroboration-redistribution
Brown, Herbert C.,Basavaiah,Bhat
, p. 1309 - 1311 (2008/10/08)
Trialkylboranes, obtained via hydroboration of terminal and cyclic alkenes with BH3-SMe2, undergo redistribution with boron tribromide at room temperature under the influence of a catalytic amount (7 mol %) of BH3·SMe2 in n-pentane to afford the corresponding alkyldibromoboranes or dialkylbromoboranes, depending upon the stoichiometry, thus providing a convenient method for preparing these valuable derivatives. The reaction of trialkylboranes derived from internal alkenes such as tri-3-hexylborane is much slower. However, these derivatives could be transformed into the corresponding alkyldibromoboranes at 70°C under neat conditions without significant isomerization. The complete conversion of tri-3-hexylborane into di-3-hexylbromoborane could not be achieved.
