First B-organyloxy-substituted iminoboranes: Preparation, stabilization, and reactivity

The amino(halo)(organyloxy)boranes ROB(X)N(H)R' (R = 2,6-(Bu2C6H3)-Bu-t, X = Cl, R' = Bu-t (7), SiMe3 (8), 2,6-(Pr2C6H3)-Pr-i (9), 2,4,6-Me3C6H2 (10), 2,4,6-(Bu3C6H2)-Bu-t (11); R = 2,6-C6H5)(2)C6H3, X = Cl, R' = Bu-t (12); R = 2,6-(Bu2C6H3)-Bu-t, X = F, R' = Bu-t (13), 2,6-(Pr2C6H3)-Pr-i (14); R = (Bu3C)-Bu-t, X = F, R' = Pr-i (15), Bu-t (18), SiMe3 (17)) were dehydrohalo genated with tert-butyllithium at low temperature. The reaction involved th e intermediate formation of an aryloxy(imino)borane in the case of 7, 9, 11 , and 12. The diazadiboretidines [ROB=NR'](2) (R = 2,6-(Bu2C6H3)-Bu-t, R' = Bu-t (18), SiMe3 (19), 2,6-(Pr2C6H3)-Pr-i (20), 2,4,6-Me3C6H2 (21); R = (B u3C)-Bu-t, R' = Pr-i (22), SiMe3 (23)) were isolated as the ultimate produc ts of the reactions. The aryloxy(imino)borane 2,6-(Bu2C6H3)-Bu-t-O-B=N-Bu-t (derived from 7) was reacted with BEt3 and Me3SiN3 to give the correspondi ng 1,2-addition products across the (B=N) triple bond (25 and 28, respectiv ely). The compounds were characterized by NMR spectroscopy (H-1,B-11, C-13, Si-29), MS (ET and FIS, and elemental analyses. X-ray structure determinat ions are presented for 18, 22, and 26.