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All total 11 Articles be found
All total 11 Articles be foundOrganoboranes. 55. Improved procedure for the conversion of representative achiral and chiral alkyl-, (E)-1-alkenyl, (Z)-1-alkenyl-, and arylboronates into the corresponding organyldichloroboranes
Brown, Herbert C.,Salunkhe, Ashok M.,Argade, Ankush B.
, p. 3094 - 3097 (1992)
Diethyl alkylboronates, R*B(OEt)2, of essentially 100% enantiomeric purity, prepared by asymmetric hydroboration of readily available prochiral alkenes, were effectively converted into the corresponding chiral alkyldichloroboranes, R*BC12, by treatment with boron trichloride (1 M solution in dichloromethane) in the presence of a catalytic amount of anhydrous ferric chloride (3 mol %). This reaction is quite general, proceeds well without detectable racemization, and is applicable to essentially optically pure boronic esters of widely varied structural requirements. The reaction is also applicable to achiral boronates, such as 1-hexyl, and hindered alkyl, such as tert-butyl. It is also applicable to the conversion of (E)- and (Z)-1-hezenylboronates, representative of the 1-alkenyl derivatives, and to phenylboronates, representative of aryl derivatives. Consequently, this procedure appears to be broadly applicable to the conversion of organylboronates, RB(OR′)2, into the corresponding organyldichloroboranes, RBCl2.
Kato et al.
, p. 1124,1125 (1962)
The preparation of pentafluorophenyldihaloboranes from pentafluorophenylmercurials C6F5HgR and BX3: the dramatic dependence of the reaction direction on the ligand R
Bardin, Vadim V.,Adonin, Nicolay Yu.
, p. 1523 - 1531 (2019/07/22)
Abstract: In search of convenient preparations of C6F5BX2 (X = Cl, Br), reactions of C6F5HgR (R = C6F5, C6H5, C2H5, Br and Cl) with BX3 were studied. Under the action of BCl3 the order of the C–Hg bond cleavage is C6F5Hg–C6H5 > C6F5–HgC2H5 > C6F5–HgC6F5 >> C6F5–HgCl. With more reactive BBr3 the sequence is C6F5Hg–C6H5 > C6F5–HgC2H5 ~ C6F5Hg–C2H5 > C6F5–HgC6F5 ≥ C6F5–HgBr. During the study we found the simple way to alkyldibromoboranes which is presented by the preparation of C2H5BBr2 from C2H5HgBr and BBr3. It is the second example of synthesis of alkylmercury derivative in an addition to the earlier reported formation of cyclopropylmercurials from di(cyclopropyl)mercury and BX3. Graphic abstract: [Figure not available: see fulltext.].
Synthesis of Boron-Halogenated Diborylamines and Diborylhydrazines by Cleavage of Stannazanes
Diemer, Stefan,Noeth, Heinrich,Storch, Wolfgang
, p. 1765 - 1780 (2007/10/03)
The diborylamines R'-N(BRX)2 (3; X=Cl, Br) are obtained by stannazane cleavage of distannylorganylamines R'-N(SnMe3)2 (4) with alkyldihaloboranes RBX2 in a 1:2 molar ratio. The presence of the sterically demanding substituents R and R' also causes carbon-tin bond cleavage, resulting in low yields of 3. However, carbon-tin bond cleavage can be suppressed by the use of bis(dimethylchlorostannyl)organylamines 5 as the nitrogen source for the synthesis of diborylamines. This results in almost quantitative yields of the compounds 3. Treatment of the distannylhydrazines R2N-N(SnMe3)2 (7) with RBX2 in a 1:2 molar ratio leads to the formation of N,N-bis(alkylhaloboryl)hydrazines 8 under mild conditions and in good yield. The molecular structures of 3 and 8 were determined by multinuclear magnetic resonance spectra in solution as well as by X-ray structure analysis in the case of 8d. A typical structural feature of 8d is the intramolecular BN adduct formation. Support for the constitutions of compounds 8c comes from MS fragmentation patterns as well as from IR spectra.
