1776-66-5Relevant articles and documents
Contributions to the Chemistry of Boron, 165 Diisopropyl- and Di-tert-butylborane Derivatives
Hoebel, Ulrike,Noeth, Heinrich,Prigge, Helene
, p. 325 - 337 (2007/10/02)
Methods for the preparation of diisopropyl- and di-tert-butylboranes R2BX (X = F, Cl, Br, I, OR', SCH3, NH2, NHR', and NR'2) are described.They use the readily accessible (dimethylamino)diorganylboranes 2a, b which are conveniently obtained from the (dimethylamino)dioxaborolane 1a by reaction with (CH3)2CHMgBr and (CH3)3CLi, respectively.The influence of the bulky groups R on the reactivity of these boranes is demonstrated for a number of examples.
Beitraege zur Chemie des Bors, 120. Tetraorganyldiborane(4): Darstellung und Stabilitaet
Noeth, Heinrich,Pommerening, Hans
, p. 3044 - 3055 (2007/10/02)
tert-Butylation of B2(OCH3)4 by LiC(CH3)3 proceeds via (CH3O)B-B(OCH3) (1) to give tri-tert-butylmethoxydiborane(4) (2).Tetraalkylation of B2(OCH3)4 is achieved by isopropyllithium; no reaction intermediates were found in this case.Al(C2H5)3 reacts with B2(OCH3)4 to give B2(C2H5)4 which is stable only below -30 deg C.On the other hand the CH3O group in 2 is replacable by CH3, and the CH3O groups in 1 by ethyl groups.Thus, product control by steric factors is evident.The thermal stability of tetraorganyldiboranes(4) is controlled by the steric screening of the boron atoms: tetraisopropyldiborane(4) decomposes slowly at room temperature, tetraethyldiborane(4) rapidly at -20 deg C.
