142294-91-5Relevant academic research and scientific papers
1,2-Diaza-3,5-diborolidines CH2BR1-(NR 2)2-BR1: Potential precursors for cyclic diborylcarbene ligands
Weber, Lothar,Foerster, Jan Benjamin,Stammler, Hans-Georg,Neumann, Beate
, p. 1711 - 1721 (2011/12/14)
The reaction of the aminohaloboranes (Me2N)(R)BX (1) (a: R = Ph, X = Cl; b: R = Me, X = Br; c: R = iPr, X = Cl) with the di-Grignard reagent (BrMg)2CH2 in ethyl ether/benzene mixtures afforded the diborylmethanes [(Me2N)(R)B]2CH2 (2) (a: R = Ph; b: R = Me; c: R = iPr), which were subsequently converted into the corresponding bis(chloroboryl)methanes [(Cl)(R)B]2CH2 (3) (a: R = Ph; b: R = Me; c: R = iPr). Base-assisted cyclocondensation of 3a-c with 1,2-diisopropylhydrazine afforded 1,2-diisopropyl-1,2-diaza-3,5-diorgano-3,5- diborolidines (4) (a: R = Ph; b: R = Me; c: R = iPr). Derivative 4a was deprotonated by potassium bis(trimethylsilyl)amide to give (1,2-diisopropyl-1,2- diaza-3,5-diphenyl-3,5-diborolidinyl)potassium (5). Attempts to introduce a halogen atom to the carbon bridge between the two boron atom by treating 5 with either iodine or 1,2-dibromoethane failed. Instead, bis(1,2-diisopropyl-1,2- diaza-3,5-diphenyl-3,5-diborolidinyl) (C-C) (6) was formed. In contrast to this, C-silylation of the heterocycle to give 7 was effected by reaction of salt 5 with trimethylsilyl chloride. Similarly, treatment of HgCl2 with two molar equivalents of 5 gave rise to the formation of bis(1,2-diisopropyl-1,2- diaza-3,5-diphenyl-3,5-diborolidinyl)mercury (8). The novel compounds were characterized by elemental analyses and various spectroscopic methods ( 1H-, 11B{1H}-, 13C{1H} NMR, MS). The molecular structures of 4a and 6-8 were elucidated by X-ray diffraction analyses. Copyright
Contributions to the Chemistry of Boron, 220. - Investigations on Diborylmethanes
Ederer, Bernd,Metzler, Nils,Noeth, Heinrich
, p. 2003 - 2010 (2007/10/02)
A convenient synthesis and spectroscopic properties of various organyl-halogen-substituted diborylmethanes (RXB)2CH2 (2a-e, R = Me, Et, iPr, Ph, Mes) are described.Reaction of bis(dichloroboryl)methane (1b) with tBuLi in a 1:2 ratio leads to isomerization of the tert-butyl group, whereas bis(dimethoxyboryl)methane (1a) reacts with 5 equivalents of tBuLi to yield tri-tert-butylborane and lithium di-tert-butylmethyleneborate (9).Borate 9 is characterized NMR-spectroscopically and by derivatization with Me3SiCl.Bis(alkinyl(dialkylamino)boryl>methanes 10a-c are obtained from the bismethanes 5a, b and LiCCPh or LiCCMe, respectively. 10c is characterized by an X-ray crystal structure analysis which allows, for the first time, a direct comparison of an sp- and an sp3-carbon atom bound to the same boron atom.Finally, an almost linear relationship between δ13C of the methylene group and δ11B in diborylmethanes has been detected. - Key Words: Diborylmethanes/ Alkynyl boranes/ Boron carbon NMR coupling fine structure
