(Iminoboryl)borate [R
<sub>3</sub>
BBNR]
<sup>−</sup>
: Durch Elektrophile E induzierte Umlagerung zu (Aminoboryl)boranen R
<sub>2</sub>
BBRNRE
作者:Stefan Luckert、Ulli Englert、Peter Paetzold
DOI:10.1002/cber.19961290318
日期:1996.3
(Iminoboryl)borates [R3BBNR]−: Rearrangement to (Aminoboryl)boranes R2BBRNRE by the Addition of Electrophiles E(Iminoboryl)borates [Li(tmeda)2][R2R′B–BNR (2a–c, R′ = Me, Me3SiCH2, Me3CCH2) are formed from the azadiboriridine NB2R3 (1, R = tBu) and LiR′ in the presence of tmeda. Vinyllithium brings about a ring expansion of 1 to give the five‐membered anionic ring [–CHCH–BRNR–BHR–]–, to which [Li(tmeda)]+ is bound (3). The (aminoboryl)boranes R2B–BMeNER (4a–c, EX = HCl, MeI, Me3SiI) are obtained, when the polar compounds EX are added to 2a, accompanied by the elimination of LiX and the migration of Me. The borate 2b reacts with HCl to give a mixture of the isomers R2B–B(CH2SiMe3)=NHR (4d) and R(Me3SiCH2)‐B–BR=NHR (4d′), and 2c reacts with HCl to yield the borane R(Me3CCH2)B–BR=NHR (4e′) exclusively. The transformation of [R2R′B–BNR]‐ to R2B–BR′ = NRE by the attack of electrophiles E corresponds to the known transformation of [R′3B–CR″] to R′2B–CR′=CR″E.