Cyclodialkenylation
3444 3450
Typical procedure for the reactions of 1,4-bis(bromomagnesio)butadiene
derivatives 2 with ketones: Magnesium powder (400 mg) in THF (5 mL)
was warmed to 508C, and 1,2-dibromoethane (0.3 mL) was added. Ten
minutes later, dibromo compound 6 (1.0 mmol) in THF (15 mL) was
added dropwise while stirring via syringe. The reaction mixture was then
stirred at 608C for 8 h. The Grignard reagent 2 was filtered under an at-
mosphere of nitrogen to remove the excess of magnesium. The ketone
(1.1 mmol) was then added to the THF solution of 2. No reaction was ob-
served.
Typical procedure for the reactions of 1,4-bis(bromagnesio)butadiene de-
rivatives 2 with PhNO: After 1,4-bis(bromomagnesio)-1,2,3,4-tetraprop-
yl-1,3-diene (2a; 1 mmol) in THF (20 mL) was generated, PhNO was
added at À308C. The reaction mixture was stirred at À308C for 2 h,
quenched with saturated aqueous NaHCO3 and followed by normal work
up and column chromatography to afford the product.
1-Phenyl-2,3,4,5-tetrapropyl-1H-pyrrole (13a): Colorless liquid (isolated
yield: 51%, 158 mg); 1H NMR (CDCl3, Me4Si): d=0.69 (t, J=7.2 Hz,
6H), 0.99 (t, J=7.2 Hz, 6H), 1.12 1.26 (m, 4H), 1.48 1.56 (m, 4H), 2.27
2.40 (m, 8H), 7.19 7.42 (m, 5H); 13C NMR (CDCl3, Me4Si): d=14.2,
14.7, 24.0, 25.4, 27.1, 27.4, 118.4, 127.2, 128.6, 128.9, 129.0, 139.8; HRMS:
m/z: calcd for C22H33N: 311.2613; found: 311.2614.
Typical procedure for the reactions of (1,3-butadiene-1,4-diyl)magnesium
reagents 3 with ketones: 1,4-Bis(bromomagnesio)-1,2,3,4-tetrapropyl-1,3-
diene (2a; 1 mmol) in THF (20 mL) was generated in situ from the corre-
sponding dibromo compound 6a (1 mmol) and Mg powder. Subsequently
the solution of 2a was cooled to room temperature. Dioxane (20 mL)
was added and the reaction mixture was stirred at room temperature for
2 h. After the mixture was filtered under an atmosphere of nitrogen to
remove the precipitate, the filtrate was evaporated in vacuo to remove
the solvent. Dioxane (15 mL) was added and the reaction mixture was
stirred for 2 h. Then the mixture was kept without stirring for 4 h and fil-
tered under an atmosphere of nitrogen to remove the precipitate again
to generate 3. The ketone (1.1 mmol) was added at room temperature.
The reaction mixture was then stirred for 0.5 h, quenched with saturated
aqueous NH4Cl, followed by normal work up and column chromatogra-
phy afforded the products.
1-Phenyl-2,3,4,5-tetramethyl-1H-pyrrole (13b): Red-orange liquid (isolat-
ed yield: 60%, 119 mg); 1H NMR (CDCl3, Me4Si): d=1.96 (s, 6H), 2.01
(s, 6H), 7.16 7.45 (m, 5H); 13C NMR (CDCl3, Me4Si): d=9.39, 10.57,
113.83, 123.64, 127.177, 128.44, 128.90, 139.46. The NMR data are consis-
tent with the reported data.[25]
Acknowledgement
This work was supported by National Science Fund for Distinguished
Young Scholars (29825105), the Major State Basic Research Develop-
ment Program (G2000077502-D), and the National Natural Science
Foundation of China (29702001 and 20172003). Cheung Kong Scholars
Programme and Qiu Shi Science & Technologies Foundation are grate-
fully acknowledged.
1,2,3,4-Tetrapropyl-5,5-diphenyl-cyclopenta-1,3-diene (4g): White solid
(isolated yield: 25%, 80 mg); b.p. 1038C; 1H NMR (CDCl3, Me4Si): d=
0.63 1.48 (m, 20H), 2.08 (t, J=6.4 Hz, 4H), 2.25 (t, J=7.8 Hz, 4H),
7.10 7.26 (m, 10H); 13C NMR (CDCl3, Me4Si): d=14.7, 14.8, 23.1, 23.4,
28.6, 29.6, 72.0, 126.0, 127.9, 128.5, 141.0, 141.9, 148.0; HRMS: m/z: calcd
for C29H38: 386.2974, found: 386.2966.
Typical procedure for the reactions of 1,4-bis(bromagnesio)butadiene de-
rivatives 2 with aldehydes: After 1,4-bis(bromomagnesio)-1,2,3,4-tetra-
propyl-1,3-diene (2a; (1 mmol) in THF (20 mL) was generated, the alde-
hyde (1.1 mmol) was added at À408C. The reaction mixture was then stir-
red for 0.5 h at À408C, quenched with saturated aqueous NH4Cl, fol-
lowed by normal work up and column chromatography to afford the
products.
[1] a) P. Knochel, W. Dohle, N. Gommermann, F. F. Kneisel, F. Kopp, T.
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Angew. Chem. Int. Ed. 2003, 42, 4302; b) R. W. Hoffmann, Chem.
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3478 3483.
Typical procedure for the reactions of (1,3-butadiene-1,4-diyl)magnesium
reagents 3 with aldehydes: After (1,3-butadiene-1,4-diyl)magnesium re-
agent 3 was generated, the aldehyde (1.1 mmol) was added at room tem-
perature. The reaction mixture was stirred for 0.5 h, quenched with satu-
rated aqueous NH4Cl, followed by normal work up and column chroma-
tography to afford the products.
Typical procedure for the reactions of 1,4-bis(bromagnesio)butadiene de-
rivatives 2 with CO2: After 1,4-bis(bromomagnesio)-1,2,3,4-tetrapropyl-
1,3-diene (2a; 1 mmol) in THF (20 mL) was generated, CO2 was bubbled
for 1 h at room temperature. The reaction mixture was quenched with sa-
turated aqueous NH4Cl and followed by normal work up and column
chromatography to afford the products.
2,3,4,5-Tetrapropyl-cyclopenta-2,4-dienone (12a): Orange liquid (isolated
yield: 47%, 117 mg); 1H NMR (CDCl3, Me4Si): d=0.81 0.91 (m, 12H),
1.30 1.38 (m, 4H), 1.45 1.55 (m, 4H), 2.05 2.16 (m, 8H); 13C NMR
(CDCl3, Me4Si): d=14.38, 14.42, 22.8, 23.2, 25.4, 28.4, 126.2, 154.6, 203.9.
The NMR data are consistent with the reported data.[22]
[7] Z. Xi, Q. Song, J. Chen, H. Guan, P. Li, Angew. Chem. 2001, 113,
1967 1970; Angew. Chem. Int. Ed. 2001, 40, 1913 1916.
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2,4-Dibutyl-3,5-diphenyl-cyclopenta-2,4-dienone (12b): Orange liquid
(isolated yield: 60%, 206 mg); 1H NMR (CDCl3, Me4Si): d=0.57 (t, J=
6.9 Hz, 3H), 0.75 (t, J=6.9 Hz, 3H), 0.80 1.53 (m, 8H), 2.12 (t, J=
6.9 Hz, 2H), 2.42 (t, J=6.9 Hz, 2H), 7.22 7.43 (m, 10H); 13C NMR
(CDCl3, Me4Si): d=13.4, 13.8, 22.4, 22.7, 22.8, 26.7, 29.9, 31.6, 125.0,
127.1, 127.9, 128.1, 128.2, 128.4, 128.5, 129.3, 131.7, 134.2, 153.5, 158.3,
202.5. The NMR data are consistent with the reported data.[22]
3,4-Dihexyl-2,5-bis-trimethylsilanyl-cyclopenta-2,4-dienone (12c): Orange
liquid (isolated yield: 10%, 39 mg); 1H NMR (CDCl3): d=0.00 (s, 18H),
0.69 0.71 (m, 6H), 1.13 1.22 (m, 16H), 2.14 2.16 (m, 4H); 13C NMR
(CDCl3, Me4Si): d=0.1, 14.0, 22.6, 28.4, 29.8, 30.7, 31.6, 128.2, 172.9,
211.2; HRMS: m/z: calcd for C23H44OSi2: 392.2931, found 392.2927.
Chem. Eur. J. 2004, 10, 3444 3450
¹ 2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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