28
H. Hagen et al. / Journal of Organometallic Chemistry 608 (2000) 27–33
2. Experimental
and Et3N (11 ml, 80 mmol) in Et2O (200 ml). Immedi-
ately a white precipitate was formed and the resulting
suspension was stirred for 24 h. After removing the
precipitate by filtration, the solvent was removed in
vacuo. Flash distillation of the residue gave a colorless
oil (16.1 g, 45%).
All reactions were performed in an atmosphere of
dry, oxygen-free dinitrogen using standard Schlenk
techniques. Solvents were carefully dried and distilled
prior to use. The phenols HOC6H4(CH2NMe2)-2 and
HOC6H3(CH2NMe2)2-2,6-Me-4 were prepared accord-
ing to literature procedures [2]. Et3N was distilled from
CaH2. B(OMe)3 was distilled from sodium sand. All
other chemicals were obtained from commercial sources
and used as received. Elemental analyses were per-
formed by H. Kolbe, Mikroanalytisches Laboratorium,
Mu¨lheim, Germany. 1H and 13C-NMR spectra were
recorded on a Bruker AC300 or a Varian Unity Inova
300 spectrometer. 11B-NMR and 19F-NMR spectra
were recorded on a Varian Unity Inova 300 spectrome-
ter both relative to an external standard, (BF3·Et2O/
CDCl3 15/85 v/v) and CFCl3/C6D6. NMR spectra were
recorded at 25°C and chemical shifts are in ppm.
1H-NMR (300 MHz, CDCl3): l 0.28 (s, 9H, SiMe3),
2.25 (s, 6H, NMe2), 3.49 (s, 2H, CH2), 6.80 (dd, 1H,
4
3
3JH,H=8, JH,H=1 Hz, ArꢀH), 6.94 (dt, 1H, JH,H=7,
4JH,H=1 Hz, ArꢀH), 7.13 (dt, 1H, JH,H=8, JH,H=2
Hz, ArꢀH), 7.31 (dd, 1H, 3JH,H=7, 4JH,H=2 Hz,
ArꢀH).
3
4
13C-NMR (75 MHz, CDCl3): l 0.5 (SiMe3), 45.4
(NMe2), 58.0 (CH2), 119.0, 121.1, 127.8, 129.4 and
131.0 (ArꢀC), 153.9 (ArꢀC1).
2.3. Synthesis of [BF2(OC6H4(CH2NMe2)-2)] (4)
Me3SiOC6H4(CH2NMe2)-2 (5.55 g, 24.8 mmol) was
added to a solution of BF3·Et2O (16.5 ml, 24.8 mmol) in
Et2O (100 ml). The resulting mixture was stirred for 7 h
after which the solvents were removed in vacuo leaving
a white solid. This solid was dissolved in CH2Cl2 (20
ml) and subsequently cooled to −20°C, which yielded
white crystals of 4 (2.47 g, 50%). M.p.: 143°C.
2.1. Synthesis of [BPh2(OC6H4(CH2NMe2)-2)] (2)
PhMgBr (1 M in Et2O, 18 ml, 18 mmol) was added
to a solution of B(OMe)3 (1 ml, 8.8 mmol) in Et2O (40
ml) at −75°C. The resulting suspension was stirred at
−75°C for 4 h after which it was allowed to warm to
room temperature. After stirring for an additional 48 h
the precipitate formed was removed by centrifugation
and subsequent decantation. Hydrochloric acid (1 M,
50 ml) was added to the decanted ethereal solution and
the biphasic system was stirred vigorously for 2 h. After
separation of the layers a solution of HOC6H4(CH2-
NMe2)-2 (1.33 g, 8.8 mmol) in Et2O (100 ml) was added
to the ethereal layer. A white precipitate was formed
and the resulting suspension was stirred for 24 h.
Removal of the solvent in vacuo and washing of the
residue with pentane (40 ml) gave a white solid. This
solid was dissolved in THF (20 ml) and subsequent
cooling of the solution to −20°C gave white crystals of
2 (0.39 g, 14%). M.p.: 182°C.
Anal. Calc. for C9H12NOBF2: C, 54.32; H, 6.08; N,
7.04; Found: C, 54.26; H, 6.19; N, 6.96%.
1H-NMR (300 MHz, CDCl3): l 2.71 (s, 6H, NMe2),
3
4
4.05 (s, 2H, CH2), 6.86 (dt, 1H, JH,H=7 Hz, JH,H=1
3
Hz, ArꢀH), 6.95 (m, 2H, ArꢀH), 7.23 (dt, 1H, JH,H=8
4
Hz, JH,H=2 Hz, ArꢀH).
13C-NMR (75 MHz, CDCl3): l 45.0 (NMe2), 60.9
(CH2), 116.0 (ArꢀC2), 119.0, 120.0, 126.7 and 129.8
(ArꢀC), 153.3 (ArꢀC1).
11B-NMR (96.3 MHz, CDCl3): l 0.76 (t, 1J19 ,11 =17
F
B
Hz).
19F-NMR (282 MHz, CDCl3): l −164.19 (1:1:1:1 q,
1J11 ,19 =17 Hz).
B
F
Anal. Calc. for C21H22NOB: C, 80.02; H, 7.04; N,
2.4. Attempted synthesis of
4.44; Found: C, 79.84; H, 6.95; N, 4.36%.
[B(OMe)2(OC6H4(CH2NMe2)-2)] (5)
1H-NMR (300 MHz, CDCl3): l 2.69 (s, 6H, NMe2),
3.77 (s, 2H, CH2), 6.8 (m, 2H, ArꢀH), 7.3 (m, 8H,
ArꢀH), 7.9 (m, 4H, ArꢀH).
A mixture of B(OMe)3 (8 ml, 70.4 mmol) and
HOC6H4(CH2NMe2)-2 (10.6 g, 70 mmol) in Et2O (300
ml) was refluxed for 10 h. After removal of the solvent
13C-NMR (75 MHz, CDCl3): l 47.3 (NMe2), 62.1
(CH2), 117.2 (OArꢀC2), 118.2 and 119.0 (OArꢀC), 126.5
(ArꢀC4), 127.1 (OArꢀC), 127.3 (ArꢀC), 129.6 (OArꢀC),
133.5 (ArꢀC), 156.0 (OArꢀC1), ArꢀC1 not observed.
11B-NMR (96.3 MHz, CDCl3): l 5.41 (br, Dw1/2=92
Hz).
1
in vacuo H-NMR analysis showed the product to be a
mixture of HOC6H4(CH2NMe2)-2 and B(OMe)2(OC6-
H4(CH2NMe2)-2) in a molar ratio of 1:2.
2.5. Synthesis of [BPh2(OC6H2(CH2NMe2)2-2,6-Me-4)]
(6)
2.2. Synthesis of Me3SiOC6H4(CH2NMe2)-2 (3)
An ethereal solution of PhMgBr (36 ml, 1 M, 36
mmol) was added to B(OMe)3 (2 ml, 17.6 mmol) in
Et2O (80 ml) at −75°C. A white precipitate was
HOC6H4(CH2NMe2)-2 (9.29 g, 61 mmol) was added
dropwise to a solution of Me3SiCl (10.1 ml, 80 mmol)