Functionalized Heterocycles
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1
[NiCl2(dppp)] (0.04 g, 0.08 mmol) in toluene (6 mL) and subsequent
treatment with NaOH (2 mL, 0.5m solution in water, 1 mmol), Et2O
(9 mL), and workup as described above yielded 28b (0.29 g, 69%) as a
658C (hexane); H NMR (CDCl3, 400 MHz): d 7.4 7.2 (m, 6H), 7.1 (d,
J 7.8 Hz, 1H), 5.1 (s, 2H), 4.3 (q, J 7.2 Hz, 2H), 1.3 (t, J 7.2 Hz, 3H);
13C NMR (CDCl3, 50.5 MHz): d 169.8, 156.1, 132.3, 130.4, 128.8, 127.8,
126.2, 124.8, 123.6, 122.5, 120.0, 69.0, 61.5, 14.0; MS (70 eV, EI): m/z(%):
1
white solid. M.p. 108 1108C (hexane); H NMR (CDCl3, 400 MHz): d
7.98 (d, J 7.6 Hz, 1H), 7.35 (dt, J 7.6, 1.6 Hz, 1H), 7.25 (dt, J 7.2, 1.6 Hz,
1H), 7.2 (d, J 7.6 Hz, 1H), 7.15 (t, J 7.6 Hz, 1H), 7.0 (dd, J 7.6, 1.2 Hz,
1H), 6.7 (dd, J 7.6, 1.2 Hz, 1H), 4.9 (s, 2H), 4.15 (s, 2H), 3.3 (brs, 2H);
13C NMR (CDCl3, 50.5 MHz): d 147.4, 137.6, 135.4, 131.3, 127.9, 127.2,
126.7, 125.5, 122.7, 121.5, 115.0, 63.6, 46.5; MS (70 eV, EI): m/z (%): 211 (48)
254 (100) [M] ; elemental analysis calcd (%) for C16H14O3 (254.3): C 75.57,
H 5.55; found: C 75.64, H 5.61.
1-(1-Hydroxy-1-phenylmethyl)-6H-dibenzo[b,d]pyran (29c): Ether 25c
(0.56 g, 2 mmol) was treated with tBuLi (4.4 mL, 1.5m solution in pentane,
6.6 mmol). Addition of benzaldehyde (0.26 g, 2.5 mmol) and workup as
described above yielded 29c (0.32 g, 56%) as a yellow solid. M.p. 47 498C
(hexane); 1H NMR (CDCl3, 400 MHz): d 7.85 7.75 (m, 1H), 7.4 7.0 (m,
11H), 6.4 (s, 1H), 5.0 (s, 2H), 2.8 (brs, 1H); 13C NMR (CDCl3, 50.5 MHz):
d 155.9, 143.6, 140.5, 134.0, 129.3, 128.9, 128.2, 127.3, 127.2, 127.1, 126.8,
124.9, 123.7, 123.3, 116.4, 72.2, 68.9; MS (70 eV, EI): m/z(%): 288 (100)
[M] , 210 (100); elemental analysis calcd (%) for C14H13NO (211.3): C
79.59, H 6.20, N 6.63; found: C 79.65, H 6.17, N 6.61.
1-Bromo-5,6-dihydrophenanthridine (28c): Amine 25b (0.64 g, 2 mmol)
was treated with tBuLi (4.7 mL, 1.5m solution in pentane, 7 mmol). 1,2-
Dibromoethane (0.56 g, 3 mmol) was added and the mixture was treated as
described above. DIBAL-H (2.0 mL, 1.5m solution in toluene, 3 mmol) was
added to a solution of the resultant residue and [NiCl2(dppp)] (0.04 g,
0.08 mmol) in toluene (6 mL). Subsequent treatment with NaOH (2 mL,
0.5m solution in water, 1 mmol) and Et2O (9 mL), and workup as described
above yielded 28c (0.38 g, 73%) as a yellow solid. M.p. 83 858C (hexane);
1H NMR (CDCl3, 400 MHz): d 8.55 (d, J 6.8 Hz, 1H), 7.4 (dt, J 8.0,
1.6 Hz, 1H), 7.3 (dt, J 7.6, 1.2 Hz, 1H), 7.2 (d, J 7.6 Hz, 2H), 6.9 (t, J
8.0 Hz, 1H), 6.65 (d, J 8.0 Hz, 1H), 4.1 (s, 3H); 13C NMR (CDCl3,
50.5 MHz): d 149.2, 135.0, 130.8, 128.6, 127.2, 126.7, 126.3, 125.5, 125.3,
[M] ; elemental analysis calcd (%) for C20H16O2 (288.3): C 83.31, H 5.59;
found: C 83.18, H 5.64.
1-Tributylstannyl-6H-dibenzo[b,d]pyran (29d): Ether 25c (0.56 g, 2 mmol)
was treated with tBuLi (4.4 mL, 1.5m solution in pentane, 6.6 mmol).
Addition of tributyltin chloride (0.83 g, 3 mmol) and workup as described
above yielded 29d (0.565 g, 60%) as a colorless oil. Rf 0.15 (hexane/ethyl
acetate 60:1); 1H NMR (CDCl3, 200 MHz): d 7.7 7.0 (m, 7H), 5.0 (s,
2H), 1.7 0.9 (m, 27H); 13C NMR (CDCl3, 50.5 MHz): d 155.9, 139.1,
133.2, 132.9, 131.8, 130.7, 128.7, 127.8, 127.1, 124.5, 124.1, 117.1, 68.8, 28.9,
122.2, 120.2, 114.5, 46.3; MS (70 eV, EI): m/z(%): 261 (50) [M2] , 259 (50)
27.2, 13.6, 11.9; MS (70 eV, EI): m/z(%): 415 [M À C4H9] (84), 301 (100);
[M] , 260 (100), 258 (100); elemental analysis calcd (%) for C13H10BrN
elemental analysis calcd (%) for C25H36OSn (471.3): C 63.72, H 7.70; found:
C 63.58, H 7.57.
(260.1): C 60.02, H 3.87, N 5.38; found: C 60.18, H 3.70, N 5.39.
5,6-Dihydro-1-tributylstannylphenanthridine (28d): Amine 25b (0.64 g,
2 mmol) was treated with tBuLi (4.7 mL, 1.5m solution in pentane,
7 mmol). Tributyltin chloride (0.96 g, 3 mmol) was added and the mixture
was treated as described above. DIBAL-H (2.0 mL, 1.5m solution in
toluene, 3 mmol) was added to a solution of the resultant residue and
[NiCl2(dppp)] (0.04 g, 0.08 mmol) in toluene (6 mL), and the subsequent
treatment with NaOH (2 mL, 0.5m solution in water, 1 mmol), Et2O
(9 mL), and workup as described above yielded 28d (0.67 g, 71%) as a
colorless oil. Rf 0.18 (ethyl acetate/hexane 20:1); 1H NMR (CDCl3,
400 MHz): d 7.55 (d, J 7.2 Hz, 1H), 7.3 (dt, J 7.6, 1.6 Hz, 1H), 7.25 (dt,
J 7.6, 1.6 Hz, 1H), 7.2 (d, J 7.6 Hz, 1H), 7.15 (t, J 7.4 Hz, 1H), 7.05 (dd,
J 7.2, 1.6 Hz, 1H), 6.7 (dd, J 7.6, 1.6 Hz, 1H), 4.2 (s, 2H), 4.0 (brs, 1H),
1.5 1.4 (m, 6H), 1.35 1.25 (m, 6H), 1.1 1.0 (m, 6H), 0.85 (t, J 7.1 Hz,
9H); 13C NMR (CDCl3, 50.5 MHz): d 147.0, 139.0, 135.0, 134.9, 130.1,
129.3, 127.8, 126.9, 126.6, 125.2, 124.6, 115.3, 46.5, 28.9, 27.2, 13.6, 11.9; MS
6H-Dibenzo[b,d]thiopyran (30a): Thioether 25d (0.59 g, 2 mmol) was
treated with tBuLi (4.4 mL, 1.5m solution in pentane, 6.6 mmol). Addition
of water (excess) and workup as described above yielded 30a (0.23 g, 59%)
as a white solid. M.p. 70 728C (hexane); 1H NMR (CDCl3, 200 MHz): d
7.8 (dd, J 7.0, 2.2 Hz, 1H), 7.7 (d, J 7.2 Hz, 1H), 7.5 7.2 (m, 6H), 3.85 (s,
2H); 13C NMR (CDCl3, 50.5 MHz): d 134.6, 134.4, 134.3, 133.6, 128.4,
127.8, 127.6, 126.9, 126.4, 125.9, 125.7, 31.7; MS (70 eV, EI): m/z(%): 198 (65)
[M] , 197 (100); elemental analysis calcd (%) for C13H10S (198.3): C 78.74,
H 5.08; found: C 78.89, H 4.97.
Ethyl 6H-dibenzo[b,d]thiopyran-1-carboxylate (30b): Thioether 25d
(0.59 g, 2 mmol) was treated with tBuLi (4.4 mL, 1.5m solution in pentane,
6.6 mmol). Addition of ethyl chloroformate (0.27 g, 2.5 mmol) and workup
as described above yielded 30b (0.27 g, 50%) as a yellow oil. Rf 0.18
(ethyl acetate/diethylamine 50:1); 1H NMR (CDCl3, 200 MHz): d 7.6 (d,
J 7.8 Hz, 1H), 7.3 7.2 (m, 6H), 4.2 (q, J 7.2 Hz, 2H), 3.8 (s, 2H), 1.1 (t,
J 7.2 Hz, 3H); 13C NMR (CDCl3, 50.5 MHz): d 170.0, 138.0, 134.7,
134.2, 133.5, 132.1, 130.4, 129.1, 128.1, 127.9, 127.0, 126.8, 126.3, 61.3, 32.3,
(70 eV, EI): m/z(%): 471 (2) [M] , 298 (100); elemental analysis calcd (%)
for C25H37NSn (470.3): C 63.85, H 7.93, N 2.98; found: C 63.78, H 8.02, N
2.90.
13.7; MS (70 eV, EI): m/z(%): 270 (100) [M] ; elemental analysis calcd (%)
for C16H14O2S (270.4): C 71.08, H 5.22; found: C 70.92, H 5.16.
General procedure for the preparation of 6H-dibenzo[b,d]pyrans 29, 33,
and 6H-dibenzo[b,d]thiopyrans (30): A solution of the starting ether 25c or
32, or thioether 25d (2 mmol) in THF (15 mL) was treated with tBuLi
(6.6 mmol, 3.3 equiv) at À1108C. The reaction mixture was stirred for
15 min at this temperature. The cooling bath was then removed to allow the
reaction to warm up to room temperature. The reaction mixture was re-
cooled to À788C, the electrophile (2.5 mmol) was added, and the mixture
was allowed to stir for 3 h at room temperature. The mixture was
hydrolyzed with water and extracted with ethyl acetate (3 Â 20 mL). The
combined organic layers were dried over anhydrous Na2SO4. After
evaporation of the solvent, the residue was purified by flash column
chromatography to afford products 29, 30, and 33.
1-[1-Hydroxy-1-(4-methylphenyl)methyl]-6H-dibenzo[b,d]thiopyran
(30c): Thioether 25d (0.59 g, 2 mmol) was treated with tBuLi (4.4 mL, 1.5m
solution in pentane, 6.6 mmol). Addition of 4-methylbenzaldehyde (0.3 g,
2.5 mmol) and workup as described above yielded 30c (0.36 g, 57%) as a
white solid. M.p. 84 868C (hexane); 1H NMR (CDCl3, 200 MHz): d
7.6 7.1 (m, 11H), 6.3 (s, 1H), 3.7 (s, 2H), 2.55 (brs, 1H), 2.4 (s, 3H);
13C NMR (CDCl3, 50.5 MHz): d 141.5, 141.2, 137.1, 136.9, 136.7, 134.6,
133.1, 129.8, 129.0, 127.8, 127.6, 127.2, 127.0, 126.6, 126.2, 72.9, 32.9, 21.0; MS
(70 eV, EI): m/z(%): 318 (6) [M] , 316 (100); elemental analysis calcd (%)
for C21H18OS (318.4): C 79.21, H 5.70; found: C 79.33, H 5.84.
2-Methoxy-6H-dibenzo[b,d]pyran (33a): Ether 32 (0.65 g, 2 mmol) was
treated with tBuLi (4.4 mL, 1.5m solution in pentane, 6.6 mmol). Addition
of water (excess) and workup as described above yielded 33a (0.34 g, 81%)
as a colorless oil. Rf 0.2 (ethyl acetate/diethylamine 40:1); 1H NMR
(CDCl3, 200 MHz): d 7.7 (d, J 7.2 Hz, 1H), 7.5 7.1 (m, 4H), 6.95 (d, J
8.8 Hz, 1H), 6.8 (dd, J 8.8, 2.8 Hz, 1H), 5.05 (s, 2H), 3.85 (s, 3H);
13C NMR (CDCl3, 50.5 MHz): d 154.8, 148.8, 131.8, 130.2, 128.3, 127.8,
124.7, 123.6, 122.0, 117.9, 115.0, 108.3, 68.6, 55.8; MS (70 eV, EI): m/z (%):
1-Bromo-6H-dibenzo[b,d]pyran (29a): Ether 25c (0.56 g, 2 mmol) was
treated with tBuLi (4.4 mL, 1.5m solution in pentane, 6.6 mmol). Addition
of 1,2-dibromoethane (0.47 g, 2.5 mmol) and workup as described above
yielded 29a (0.32 g, 61%) as a white solid. M.p. 54 568C (hexane);
1H NMR (CDCl3, 400 MHz): d 8.55 (d, J 7.6 Hz, 1H), 7.4 (t, J 7.6 Hz,
1H), 7.4 7.3 (m, 2H), 7.2 (d, J 6.8 Hz, 1H), 7.1 7.0 (m, 2H), 4.95 (s, 2H);
13C NMR (CDCl3, 50.5 MHz): d 157.3, 133.2, 129.3, 129.1, 128.6, 127.9,
127.6, 126.3, 124.7, 123.7, 119.7, 116.8, 69.2; MS (70 eV, EI): m/z(%): 262 (71)
212 (100) [M] ; elemental analysis calcd (%) for C14H12O2 (212.2): C 79.22,
[M2] , 261 (100), 260 (67) [M] , 259 (87); elemental analysis calcd (%)
H 5.70; found: C 78.99, H 5.73.
for C13H9BrO (261.1): C 59.80, H 3.47; found: C 60.02, H 3.41.
Ethyl 2-methoxy-6H-dibenzo[b,d]pyran-1-carboxylate (33b): Ether 32
(0.65 g, 2 mmol) was treated with tBuLi (4.4 mL, 1.5m solution in pentane,
6.6 mmol). Addition of ethyl chloroformate (0.27 g, 2.5 mmol) and workup
as described above yielded 33b (0.43 g, 75%) as a white solid. M.p. 71
738C (hexane); 1H NMR (CDCl3, 200 MHz): d 7.65 7.55 (m, 1H),
Ethyl 6H-dibenzo[b,d]pyran-1-carboxylate (29b): Ether 25c (0.56 g,
2 mmol) was treated with tBuLi (4.4 mL, 1.5m solution in pentane,
6.6 mmol). Addition of ethyl chloroformate (0.27 g, 2.5 mmol) and workup
as described above yielded 29b (0.35 g, 68%) as a yellow solid. M.p. 63
Chem. Eur. J. 2002, 8, No. 9
¹ WILEY-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002
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