First B-Organyloxy-Substituted Iminoboranes: Preparation, Stabilization, and Reactivity

The amino(halo)(organyloxy)boranes ROB(X)N(H)R‘ (R = 2,6-tBu2C6H3, X = Cl, R‘ = tBu
(7), SiMe3 (8), 2,6-iPr2C6H3 (9), 2,4,6-Me3C6H2 (10), 2,4,6-tBu3C6H2 (11); R = 2,6-C6H5)2C6H3,
X = Cl, R‘ = tBu (12); R = 2,6-tBu2C6H3, X = F, R‘ = tBu (13), 2,6-iPr2C6H3 (14); R = tBu3C,
X = F, R‘ = iPr (15), tBu (16), SiMe3 (17)) were dehydrohalogenated with tert-butyllithium
at low temperature. The reaction involved the intermediate formation of an aryloxy(imino)borane in the case of 7, 9, 11, and 12. The diazadiboretidines [ROBNR‘]2 (R = 2,6-tBu2C6H3,
R‘ = tBu (18), SiMe3 (19), 2,6-iPr2C6H3 (20), 2,4,6-Me3C6H2 (21); R = tBu3C, R‘ = iPr (22),
SiMe3 (23)) were isolated as the ultimate products of the reactions. The aryloxy(imino)borane 2,6-tBu2C6H3−O−B⋮N-tBu (derived from 7) was reacted with BEt3 and Me3SiN3 to
give the corresponding 1,2-addition products across the (B≡N) triple bond (25 and 26,
respectively). The compounds were characterized by NMR spectroscopy (1H, 11B, 13C, 29Si),
MS (EI and FI), and elemental analyses. X-ray structure determinations are presented for
18, 22, and 26.