1‐Azonia‐2‐boratanaphthalenes

The 1‐azonia‐2‐boratanaphthalenes (NH)(BX)C 8 H 6 can be synthesized from 2‐aminostyrene and the dihaloboranes XBHal 2 ( 1 ‐ 4 : X = Cl, Br, i Pr, t Bu). Further derivatives (NH)(BX)C 8 H 6 are obtained from 1 by replacing Cl by alkoxy or alkyl groups [ 5 ‐ 8 : X = OMe, O t Bu, Me, (CH 2 ) 3 NMe 2 ]. The hydrolysis of 1 gives a mixture of the bis(azoniaboratanaphthyl) oxide [(NH)BC 8 H 6 ] 2 O ( 9 ) and the hydroxy derivative (NH)[B(OH)]C 8 H 6 ( 10 ). The diboryl oxide 9 crystallizes in the space group C 2/ c . The lithiation of 4 at the nitrogen atom gives [NLi(tmen)](B t Bu)C 8 H 6 ( 11 ), which upon reaction with the diborane(4) B 2 Cl 2 (NMe 2 ) 2 yields the 1, 2‐bis(azoniaboratanaphthyl)diborane B 2 [N(B t Bu)C 8 H 6 ] 2 (NMe 2 ) 2 ( 12 ). The 2‐chloro‐1‐methyl‐4‐phenyl derivative (NMe)(BCl)C 8 H 5 Ph ( 13 ) of the parent (NH)(BH)C 8 H 6 can be synthesized from the aminoborane BCl 2 (NMePh) and phenylethyne. Substitution of Cl in 13 gives the derivatives (NMe)(BX)C 8 H 5 Ph [ 14 ‐ 20 : X = N(SiMe 3 ) 2 , Me, Et, i Bu, t Bu, CH 2 SiMe 3 , Ph] and the reaction of 13 with Li 2 O affords the bis(azoniaboratanaphthyl) oxide [(NMe)BC 8 H 5 Ph] 2 O ( 21 ). The reaction of 16 or 19 with [(MeCN) 3 Cr(CO) 3 ] yields the complexes [{(NMe)(BX)C 8 H 5 Ph}Cr(CO) 3 ] ( 22 , 23 : X = Et, CH 2 SiMe 3 ), in which the chromium atom is hexahapto bound to the homoarene part of 16 or 19 , respectively. The complex 23 crystallizes in the space group P 2 1 / c . Upon reaction of the phenols para ‐C 6 H 4 R(OH) with the aryldichloroboranes ArBCl 2 and subsequent condensation of the products with phenylethyne, the 1‐oxonia‐2‐boratanaphthalenes O(BAr)C 8 H 4 RPh with R in position 6 and Ph in position 4 are formed ( 24 ‐ 26 : Ar = Ph, R = H, Me, OMe; 27 ‐ 29 : Ar = C 6 F 5 , R = H, Me, OMe). The azoniaboratanaphthalenes 1 ‐ 23 were characterized by NMR methods.