P. Langer et al.
FULL PAPER
[Ph2C C C C(C12H8O)]; elemental analysis calcd (%) for C41H28O4: C
84.23; H 4.83; found: C 84.46, H 4.60.
129.11, 129.32, 129.81, 129.85, 130.46, 131.23, 131.33, 131.70, 132.74, 132.86,
133.37, 133.64, 134.94, 136.72, 140.24, 141.03, 141.78, 142.96, 143.64, 146.27;
MS (CI, NH3): m/z: 659 [M 1].
Preparation of 5,10,10,11-tetraphenyl-10H-benzo[b]fluorenes (9): Allene
8a (200 mg, 0.36 mmol) and para-toluenesulfonic acid (60 mg) were heated
in toluene (30 mL) at 808C for 2 h. The color of the solution changed from
light yellow to deep orange. The crude mixture was purified by column
chromatography (silica gel, diethyl ether:petroleum ether 1:5 ! 1:1) to give
9a (159 mg, 85%) as orange crystals. M.p. 1768C; 1H NMR (CDCl3,
200 MHz): d 6.20 (d, J 7 Hz, 1H; Ar), 6.56 (m, 2H; Ar), 6.71 (d, J
7 Hz, 1H; Ar), 6.11 (dd, J 7 Hz, J 1.5 Hz, 1H; Ar), 6.41 (m, 2H; Ar),
6.58 (m, 3H; Ar), 6.85 ± 7.25 (m, 18H; Ar); 13C NMR (CDCl3, 50 MHz):
dc 57.42 (C, CPh2), 119.89, 123.25, 124.70, 126.05, 126.23, 127.33, 127.34,
127.81, 127.99, 128.08, 128.20, 128.77, 128.99, 129.28, 130.14, 130.15, 130.37
(CH, Ar), 133.57, 133.81, 134.32, 135.51, 137.78, 139.80, 140.13, 142.24,
145.54, 145.82, 147.23 (C, Ar); IR (KBr): nÄ 3056 (m), 3024 (m), 2924 (m),
1600 (m), 1492 (m), 1448 (m), 1368 (w), 1076 (w), 1032 (w), 760 (s), 744 (s),
11a: Yield: 85%; 1H NMR (CDCl3, 250 MHz): d 7.20 ± 7.80 (m, 18H;
Ar); 13C NMR (CDCl3, 75 MHz): dc 120.13, 123.39, 127.15 (CH), 127.46
(C), 128.29, 128.61 (CH), 128.75 (C), 128.88, 129.64 (CH), 138.48, 139.00,
139.73, 146.66, 151.93 (C); MS (EI): m/z (%): 354 (100) [M ]; elemental
analysis calcd (%) for C28H18: C 94.88, H 5.12; found: C 94.56, H 4.94.
11b: Yield: 70%; 1H NMR (CDCl3, 250 MHz): d 7.10 ± 7.20, 7.25 ± 7.55,
7.65 (m, 18H; Ar); 13C NMR (CDCl3, 75 MHz, APT): dc 110.49 (C),
116.85 (CH), 118.89 (C), 121.74 (C), 123.98, 127.48, 127.70, 128.50, 129.23,
129.67 (CH), 137.20, 139.24, 150.90, 151.22 (C); MS (EI): m/z (%): 370 (100)
[M ]; elemental analysis calcd (%) for C28H18O: C 90.78, H 4.90; found: C
90.48, H 4.72.
General procedure for the generation of trisilylated allenes from silyl enol
ethers: All reactions were carried out on a 4 ± 10 mmol scale. To a solution
of LDA (26.4 mmol, 4.4 equiv) in THF (50 mL) [prepared by the addition
of nBuLi (18.1 mL) to a solution of diisopropylamine (4.0 mL) in THF
(50 mL)], was added a solution of the silyl enol ether (1 equiv) in THF
(10 mL) at 08C. The ice bath was removed and the solution was stirred at
208C for 6 h. A solution of Me3SiCl (4.5 equiv) in THF (10 mL) was added
at 08C. The reaction was worked-up according to the procedure given for
the preparation of allene 6a.
724 (s), 700 (s) cm 1; MS (FAB): m/z: 521 (100) [M 1]; elemental analysis
calcd (%) for C41H28: C 94.58, H 5.42; found: C 94.27, H 5.50. During the
formation of 9a, benzofulvene 10b was isolated as a sideproduct in low
yield: 1H NMR (CDCl3, 250 MHz): d 6.85 ± 7.65 (m, Ar).
Conditions for the separation of the enantiomers of (9a): Stationary phase:
tris(phenylcarbamoyl)cellulose/SiO2; eluent: EtOH; UV detection: l
1
320 nm; polarimetric detection: l 436 nm; c 1 mgmL (injection of
50 mL); p 63 bar; T 258C; flow: 0.5 mLmin 1; t1 9 min; k1' 0.44.
These results were independently confirmed by the use of different
conditions: stationary phase: triacetylcellulose/SiO2; eluent: MeOH; UV
Tris(trimethylsilyl)-(2'-quinolyl)allene (16): Prepared from 15 (1.80 g,
6 mmol) and Me3SiCl (3.5 mL, 4.5 equiv). Isolated by chromatography
(activated Al2O3, hexane) as a yellow oil (1.95 g, 85%); 1H NMR (CDCl3,
300 MHz): d 0.19 (s, 18H; Me3Si), 0.31 (s, 9H; Me3Si), 7.35 (t, 1H; Ar);
1
detection: l 278 nm; polarimetric detection: l 405 nm; c 1 mgmL
1
(injection of 150 mL); p 68 bar; T 258C; flow: 1.0 mLmin
12.6 min; k1' 0.60.
;
t1
7.42 (d, 1H; Ar), 7.57 (t, 1H; Ar), 7.68 (d, 1H; Ar), 7.87, 7.88 (d, 2H; Ar);
13
C NMR (CDCl3, 75 MHz): dC 0.04, 0.48 (Me3Si), 83.98, 85.94 (C, CSi,
9b: Yield: 73%; 1H NMR (CDCl3, 250 MHz): d 3.76, 3.78 (2 Â s, 2 Â 3H;
OCH3), 5.75 (d, 2H; Ar), 6.30 (s, 1H; Ar), 6.40 ± 6.70 (m, 6H; Ar), 6.80 ±
7.20 (m, 17H; Ar), 7.40 ± 7.70 (m, 6H; Ar); 13C NMR (CDCl3, 75 MHz):
dc 55.15, 55.31 (OCH3), 56.84 (C, CPh2), 112.64, 113.22, 121.71, 125.65,
125.83, 126.10, 126.94, 127.24, 127.56, 127.76, 127.93, 128.61, 129.04, 129.11,
129.36, 130.13, 130.32, 131.19 (CH), 131.81, 132.92, 133.69, 134.75, 135.29,
135.93, 137.93, 138.05, 138.95, 142.29, 144.14, 147.43, 155.00, 157.61 (C); MS
CSi2), 119.61, 124.72, 125.77, 127.21, 128.77, 128.86, 135.01, 148.28 (CH, C,
Ar), 208.98 (C, C C C); 29Si NMR: (CDCl3): dSi
5.07, 2.76; IR
(CHCl3): nÄ 1887 (C C C), 1249 (Me3Si) cm 1; elemental analysis calcd
(%) for C21H33NSi3: C 65.73, H 8.67; found: C 66.20, H 8.61.
Tris(trimethylsilyl)-(2'-pyridyl)allene (18): Prepared from 17 (750 mg,
3 mmol) and Me3SiCl (1.75 mL, 4.5 equiv). Isolated by preparative GC as
a yellow oil (18%, GC); 1H NMR (CDCl3, 300 MHz): d 0.13 (s, 18H;
Me3Si), 0.20 (s, 9H; Me3Si), 6.90, 7.37, 7.48, 7.47 (m, 4H; Pyr); 13C NMR
(EI): m/z: 580 [M ], 374 [88]; elemental analysis calcd (%) for C43H32O2: C
88.94, H 5.55; found: C 88.68, H 5.44.
(CDCl3, 75 MHz): dc 0.01, 0.40 (Me3Si), 84.40, 84.72 (C, CSi, CSi2),
9c: Yield: 76%; 1H NMR (CDCl3, 250 MHz): d 3.25 (s, 3H; OCH3), 3.36
(s, 2 Â 3H; OCH3), 3.37 (s, 3H; OCH3), 6.19 (m, 1H; Ar), 6.50 ± 7.10 (m,
11H; Ar), 7.15 ± 7.50 (m, 12H; Ar); 13C NMR (C6D6, 75 MHz): dc 54.73,
54.79 (OCH3), 57.15 (C, CPh2), 110.65, 113.18, 113.34, 113.37, 113.67, 120.93,
126.46, 128.07 (CH), 128.12, 128.73 (C), 129.28, 129.63, 130.29, 130.56,
131.71, 132.40 (CH), 134.59, 135.70, 136.25, 138.43, 138.60, 139.32, 139.40,
139.63, 143.05, 148.24, 158.44, 158.62 (C); MS (EI): m/z (%): 640 (100)
118.73, 120.68, 135.39, 148.73 (CH, Pyr), 159.73 (C, Pyr), 208.98 (C,
C C C); IR (CHCl3): nÄ 1888 (s, C C C), 1252 (s, Me3Si) cm 1; MS
(208C): m/z: 333 [M ].
Tris(trimethylsilyl)phenylallene (20): Prepared from 19 (753 mg, 3 mmol)
and Me3SiCl (1.75 mL, 4.5 equiv).
A complex reaction mixture was
obtained. An nonpolar fraction (280 mg) was obtained by chromatography
(silica gel, hexane). The 1H NMR, MS, and IR data indicated the presence
of 20 by comparison with the data reported for this compound in the
[M ], 533 (42); elemental analysis calcd (%) for C45H36O4: C 84.35, H 5.66;
found: C 84.46, H 5.56.
literature.[30] IR (CHCl3): 1880 (s, C C C), 1248 (s, Me3Si) cm 1; MS
(208C): m/z: 332 [M ].
During the formation of 9c, benzofulvene 10a was isolated as a side
product in 10% yield; 1H NMR (CDCl3, 250 MHz): d 3.49 (s, 3H;
OCH3), 3.90 (s, 3H; OCH3), 6.21 (d, J 2 Hz, 1H; Ar), 6.60 (s, 1H; Ar),
6.75 (dd, J 2 Hz, J 7 Hz, 1H; Ar), 6.96 (m, 2H; Ar), 7.35 ± 7.65 (m, 13H;
Ar); 13C NMR (CDCl3, 62.5 MHz): dc 55.06, 55.33 (OCH3), 109.94,
112.72, 113.97, 120.43, 124.84, 127.87, 127.96, 128.34 (CH), 128.49 (C),
128.66, 128.73, 130.22, 131.42 (CH), 136.04, 138.11, 139.04, 141.65, 142.30,
Lithiation of silyl enol ether (23): Prepared from 23 (753 mg, 3 mmol) and
Me3SiCl (1.75 mL, 4.5 equiv). A complex reaction mixture was obtained.
Presence of an allene product was detected by IR. GC-MS indicated
formation of 24 as the main product which was isolated by preparative GC
(52%); 1H NMR (CDCl3, 300 MHz): d 0.07 (s, 6H; Me2Si), 0.09 (s, 9H;
Me3Si), 0.86 (s, 9H; tBu), 1.52 (d, J 10 Hz, 2H; CH2), 5.2 (t, J 10 Hz,
143.89, 145.30, 157.67, 159.32 (C); MS (EI): 416 (100) [M ]; MS (CI, NH3):
1H; CH-), 7.10 ± 7.40 (m, 4H; Ph).
m/z: 417 [M 1]; elemental analysis calcd (%) for C30H24O2: C 86.51, H
General procedure for the preparation of silyl imino ethers (25), (27), and
(32): To a solution of LDA (27.5 mmol) in THF (50 mL) [prepared by
addition of nBuLi (18.9 mL) to a solution of diisopropylamine (4.1 mL) in
THF], was added a solution of the amide (25 mmol) in THF (10 mL) at
08C. The color of the solution became yellow. After the mixture had been
stirred at 208C for 2h, a solution of tBuMe2SiCl (5.6 g, 1.5 equiv) in THF
(10 mL) was added and the precipitation of LiCl was observed. The
suspension was stirred for 48 h at 208C. The solvent was removed and the
residue was dried in vacuo and extracted with hexane (3 Â 80 mL). The
extracts were filtered through Celite and the solvent was removed in vacuo.
5.81; found: C 86.35, H 5.62.
1
9d: Yield: 83%; H NMR (CDCl3, 250 MHz): d 2.20 (s, 3H; CH3), 2.30
(s, 3 Â 3H; CH3), 6.02 (s, 1H; Ar), 6.55 (d, 2H; Ar), 6.70 ± 7.70 (m, 21H;
Ar); 13C NMR (CDCl3, 62.5 MHz): dc 20.87, 21.13, 21.52 (CH3), 56.92 (C,
CPh2), 119.56, 124.28, 126.04, 127.58, 127.71, 127.82, 127.89, 128.19, 128.44,
128.51, 128.85, 128.99, 129.21, 129.39, 130.05, 130.12, 130.46, 131.52, 132.73,
133.94, 133.97, 134.06, 134.66, 135.21, 135.33, 137.99, 139.11, 139.70, 142.28,
143.02, 143.21, 147.40; MS (EI): m/z (%): 576 (36) [M ], 384 (100);
elemental analysis calcd (%) for C45H36: C 93.71, H 6.29; found: C 93.58, H
6.18.
9e: Yield: 86%; 1H NMR (CDCl3, 250 MHz): d 6.20 (s, 1H; Ar), 6.58 (d,
J 1.5 Hz, 2H; Ar), 7.10 ± 7.70 (m, 21H; Ar); 13C NMR (CDCl3,
62.5 MHz): dc 56.87 (C, CPh2), 120.68, 123.86, 125.38, 127.07, 127.46,
127.84, 127.93, 128.13, 128.31, 128.72, 128.76, 128.81, 128.87, 128.92, 129.03,
tert-Butyldimethyl[(1-phenylimino)ethyloxy]silane (25): Prepared from
acetanilide (4.42 g, 32.8 mmol). Yellow oil (6.7 g, 82%) which was purified
for elemental analysis by preparative GC. 1H NMR (CDCl3, 300 MHz):
d 0.31 (s, 6H; Me2Si), 0.95 (s, 9H; tBu), 1.79 (s, 3H; CH3), 7.00 ± 7.30 (m,
5H; Ph); 13C NMR (CDCl3, 75 MHz): dC 4.55 (CH3, Me2Si), 17.13
582
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Chem. Eur. J. 2001, 7, No. 3