E. Cadoni et al. / Tetrahedron 65 (2009) 2279–2284
2283
75.4 MHz):
d
¼164.2, 144.2, 143.2, 124.5, 123.8, 123.3, 114.1, 113.3,
reaction was completed in 15 h and the reaction mixture was
worked up as described above. The crude product was purified by
crystallization (EtOH/H2O) to give 9c (695 mg, 50% yield) as
amorphous white solid, mp 299–300 ꢀC (with decomposition). IR
109.4 ppm. MS (EI): m/z (%)¼272 (36, Mþ), 255 (5), 228 (22), 136
(14), 119 (14), 92 (100), 64 (48), 63 (45), 52 (11). Anal. Calcd for
C14H8O6: C, 61.77; H, 2.96. Found: C, 61.65; H, 2.91.
(KBr):
1037, 948, 783, 743 cmꢁ1
J¼1.9 Hz, 2H, ArH), 7.66 (d, J¼1.8 Hz, 2H, ArH), 7.36 (t, J¼1.9 Hz, 2H,
n
¼2966 (br), 2689, 2576, 1695, 1487, 1461, 1422, 1307, 1190,
4.8. 10,30-Benzodioxol-20-spiro-(4-bromo-1,
3-benzodioxole) (7d)
.
1H NMR (DMSO, 300 MHz):
d
¼7.75 (d,
ArH) ppm. 13C NMR (DMSO, 75.4 MHz):
d¼164.1, 144.1, 143.1, 124.7,
A solution of Br2 (0.34 mL, 4.4 mmol) in dry THF (10 mL) was
added dropwise to a solution of 6 in THF, prepared as described
above, and the reaction was completed by vigorously stirring for 1 h
at the same temperature. The cooling bath was removed and the
reaction mixture was worked up as described above. The crude
product was purified by chromatography (PE) to give 7d (0.4 g, 80%
yield) as amorphous white solid, mp 56.5–58.5 ꢀC, Rf¼0.54 (PE). IR
123.5, 114.2, 113.4 ppm. MS (EI): m/z (%)¼316 (37, Mþ), 299 (5), 272
(15), 181 (7), 180 (3), 163 (6), 136 (28), 119 (41), 108 (7), 107 (4), 92
(100), 91 (91), 79 (10), 64 (20), 63 (40), 52 (14), 51 (14), 44 (16).
Anal. Calcd for C15H8O8: C, 56.97; H, 2.55. Found: C, 56.82; H, 2.59.
4.12. 4,40-Bi-[2,20-spirobi-(1,3-benzodioxole)] (11)
(KBr):
743 cmꢁ1. 1H NMR (CDCl3, 300 MHz):
ArH), 6.95 (m, 4H, ArH), 6.86 (m, 2H, ArH) ppm. 13C NMR (CDCl3,
n
¼2923, 2853, 1622, 1472, 1455, 1242, 1183, 996, 763,
Method C. A solution of ZnBr2 (1.8 g, 2.8 mmol) in THF (8 mL)
was added dropwise to the solution of 6 (2.28 mmol) in THF (10 mL)
prepared as described above and the reaction mixture was main-
tained by vigorously stirring for 30 min at the same temperature.
The cooling bath was removed and the temperature increased to
23 ꢀC: after 1 h 10 was formed, then compound 7d (0.859 g,
2.8 mmol) in THF (3 mL) was added and after 5 min Pd(Ph3)4
(0.016 g, 0.014 mmol) in THF (3 mL) was added; the reaction was
completed in 20 h. The reaction mixture was hydrolyzed with
aqueous NH4Cl (10%). The organic layer was separated and the
aqueous layer was extracted with CH2Cl2 (3ꢂ20 mL); the organic
phases were combined, dried (Na2SO4) and concentrated.
Method D. A solution of 4-bromotoluene (0.35 mL, 2.8 mmol) in
THF (3 mL) was added dropwise to the solution of 10 prepared as
described above, after 5 min Pd(Ph3)4 (0.016 g, 0.014 mmol) in THF
(3 mL) was added and the reaction was maintained by stirring for
20 h at the same temperature. The reaction mixture was hydro-
lyzed with aqueous NH4Cl (10%). The organic layer was separated
and the aqueous layer was extracted with CH2Cl2 (3ꢂ20 mL); the
organic phases were combined, dried (Na2SO4) and concentrated.
Purified by chromatography (Et2O/PE, 1:4); white crystals (EtOH/
hexane), 0.31 g, yield 62%, mp 206–208 ꢀC, Rf¼0.68 (Et2O/PE, 1:4).
d
¼7.16 (dd, J¼8.0, 1.2 Hz, 1H,
75.4 MHz):
d
¼144.3, 143.9, 142.5, 126.0, 123.6, 122.7, 108.7, 107.7,
100.7 ppm. MS (EI): m/z (%)¼308 (98, Mþþ2), 306 (100, Mþ), 200
(7), 198 (7), 172 (17), 170 (17), 155 (6), 136 (8), 120 (25), 107 (5), 92
(40), 64 (40), 63 (60), 52 (12), 51 (10). Anal. Calcd for C13H7BrO4: C,
50.84; H, 2.30. Found: C, 50.79; H, 2.26.
4.9. 2,20-Spirobi-(4-methyl-1,3-benzodioxole) (9a)
A 1.4 M solution of s-BuLi (3.3 mL, 4.62 mol) in cyclohexane was
added dropwise (very slowly) to a vigorously stirred solution of 3
(0.5 g, 2.2 mmol) in dry THF (10 mL) at ꢁ75 ꢀC under argon: after
30 min, the dilithium carbanion 8 was formed. A solution of
(CH3)2SO4 (6.6 mmol) in dry THF (5 mL) was added dropwise and
the reaction was completed by vigorously stirring for 1 h at the
same temperature. The cooling bath was removed and the reaction
mixture was worked up as described above. The crude product was
purified by chromatography (PE) to give 9a (406 mg, 72% yield) as
white needles, mp 80–81 ꢀC, Rf¼0.51 (PE). IR (KBr):
¼2924, 1655,
n
1609, 1489, 1464, 1267, 1251, 1227, 1186, 1159, 1085, 1063, 986, 941,
853, 779, 759, 719, 785 cmꢁ1
.
1H NMR (CDCl3, 300 MHz):
d¼6.85
IR (KBr)
n
¼3082, 2924, 1642, 1590, 1484, 1431, 1239, 1171 (br), 993,
(m, 6H, ArH), 2.27 (s, 6H, CH3) ppm. 13C NMR (CDCl3, 75.4 MHz):
775, 755. 1H NMR (300 MHz, CDCl3):
d
¼7.47 (dd, J¼8.1, 1.3 Hz, 2H,
ArH), 7.08 (t, J¼8.1 Hz, 2H, ArH), 7.02–6.98 (m, 10H, ArH) ppm. 13C
d
¼143.6, 142.6, 124.4, 122.8, 122.3, 119.3, 106.0, 14.4 ppm. MS (EI):
m/z (%)¼256 (40, Mþ), 175 (16), 134 (3.4), 106 (31), 105 (77), 89 (8),
78 (100), 77 (54). Anal. Calcd for C15H12O4: C, 70.31; H, 4.72. Found:
C, 70.19; H, 4.78.
NMR (75.4 MHz, CDCl3):
d¼144.6, 144.2, 141.4, 123.5, 122.8, 122.8,
117.3, 108.9, 108.4 ppm. MS (EI): m/z (%)¼454 (100, Mþ), 318 (24),
290 (6), 262 (5), 261 (4), 182 (10), 154 (19), 126 (30), 92 (6), 64 (16),
63 (14). Anal. Calcd for C26H14O8: C, 68.73; H, 3.11. Found: C, 68.70;
H, 3.13.
4.10. 2,20-Spirobi-(1,3-benzodioxol-4-carbaldehyde) (9b)
4.13. Experimental data for the crystal structure of 1135
A solution of DMF (0.34 mL, 4.4 mmol) was added dropwise to
a solution of 8 in THF, prepared as described above, and the reaction
was completed by vigorously stirring for 1 h at the same temper-
ature. The cooling bath was removed and the reaction mixture was
worked up as described above. The crude product was purified by
crystallization (EtOH/H2O) to give 9b (310 mg, 50% yield) as white
Formula C26H14O8, M¼454.37, white crystals 0.42ꢂ0.35ꢂ0.30
mm3, a¼8.4831(1) Å, b¼22.4949(3) Å, c¼10.8643(1) Å,
a
¼90ꢀ,
b
¼99.420(1)ꢀ,
g
¼90ꢀ, V¼2045.24(4) Å3, rcalcd¼1.476 g/cm3,
m
¼0.111 mmꢁ1, Z¼4, monoclinic, space group P2(1)/n,
¼0.71073 Å,
l
needles, mp 167–168 ꢀC. IR (KBr):
n
¼3069, 3035, 2833, 2748, 1694,
T¼296(2) K, 48,703 reflections collected.
1638, 1460, 1367, 1249, 1193, 1166, 967, 784, 706 cmꢁ1
.
1H NMR
(DMSO, 300 MHz):
d
¼10.20 (s, 2H, ArH), 7.77 (d, J¼8.1 Hz, 2H, ArH),
Acknowledgements
7.76 (d, J¼7.8 Hz, 2H, ArH), 7.48 (m, 2H, ArH) ppm. 13C NMR (DMSO,
75.4 MHz):
d¼188.5, 144.2, 142.7, 124.6, 124.2, 119.6, 114.8 ppm. MS
`
Financial support from the Ministero dell’Universita e della
Ricerca Scientifica e Tecnologica (Rome) and University of Cagliari is
gratefully acknowledged.
(EI): m/z (%)¼284 (40, Mþ), 256 (10), 165 (9), 163 (16), 149 (12), 120
(38), 119 (79), 92 (66), 91 (43), 74 (25), 64 (39), 63 (100), 62 (31), 53
(16), 50 (25), 38 (16). Anal. Calcd for C15H8O6: C, 63.39; H, 2.84.
Found: C, 63.22; H, 2.80.
References and notes
4.11. 2,20-Spirobi-(1,3-benzodioxol-4-carboxylic) acid (9c)
1. (a) Brunel, J. M. Chem. Rev. 2005, 105, 857–897; (b) Kim, K. H.; Jeong, C.-K.; Kim,
D.-H.; Ha, D.-C. Tetrahedron: Asymmetry 2006, 17, 1688–1692; (c) Saha, B.; Ra-
janBabu, T. V. J. Org. Chem. 2007, 72, 2357–2363; (d) Bartoszek, M.; Beller, M.;
Deutsch, J.; Klawonn, M.; Kockritz, A.; Nemati, N.; Pews-Davtyan, A. Tetrahedron
2008, 64, 1316–1322.
A solution of 8 in THF, prepared as described above, was injected
by a syringe in a flask containing crushed solid CO2 (ca. 100 g). The