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DOI: 10.1055/s-0028-1083627
Zinc(II) Iodide-Triethylsilane: A Novel Mild Reduction System for Direct Deoxygenation of Aryl Aldehydes, Ketones, and α,β-Unsaturated Enones
Publikationsverlauf
Publikationsdatum:
12. November 2008 (online)
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Abstract
ZnI2-TESH has been found to be a novel mild and efficient reduction system. This reagent, in contrast to the traditional ionic deoxygenation systems (TFA-R3SiH, BF3˙OEt2-R3SiH, etc.), could directly deoxygenate different kinds of carbonyl compounds such as aryl aldehydes, ketones, and α,β-unsaturated enones to the corresponding hydrocarbons in moderate to excellent yields.
Key words
zinc iodide - ionic hydrogenation - deoxygenation - carbonyl compounds - hydrocarbons
- Supporting Information for this article is available online:
- Supporting Information
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References and Notes
Deng, G.; Zhao, X. L.; Li, Z.; Jiang, B.; Li, Y. C. unpublished results.
19General Procedure for the Synthesis of Product 2: To a stirred solution of substrate 1 (1 mmol) in 1,2-dichloroethane (5 mL) at r.t. was added solid zinc iodide (638 mg, 2 mmol).Then, triethylsilane (1.9 mL, 10 mmol) was added slowly to the above suspension via a syringe. The reaction mixture was stirred at r.t. until 1 was completely disappeared or there was no further conversion (TLC inspection). The stirring was stopped, and then the reaction mixture was filtered through Celite. The Celite was washed with CH2Cl2 (4 × 15 mL). The combined filtrate was washed with H2O and sat. brine, and then dried over anhyd Na2SO4. After concentration, the residue was chromatographed on silica gel, eluting with 0-25% EtOAc in cyclohexane.
20
Analytic Data
for 4-Chloro-2-[2,2,2-trifluoro-1-(triethyl-silyloxy)ethyl]aniline
(2j): ¹H NMR (300 MHz,
CDCl3): δ = 0.62
(q, J = 7.9 Hz, 6 H), 0.92 (t, J = 7.9 Hz, 9 H), 3.93 (br s,
2 H), 4.94 (q, J = 7.2 Hz, 1
H), 6.60 (d, J = 8.5 Hz,
1
H), 7.09 (dd, J = 8.5, 2.5 Hz,
1 H), 7.15 (d, J = 2.5 Hz, 1 H).
MS (EI): m/z (%) = 339 (39) [M+],
322 (4), 310 (43), 190 (32), 188 (100), 77 (36). HRMS (EI): m/z
calcd for C14H21NOSiClF3: 339.1033;
found: 339.1041.
Analytic Data
for 5-[(4-Hydroxy-3-methoxyphenyl)-methyl]-2-methoxy-4-methylphenol
(2d-2): ¹H NMR (300 MHz, CDCl3): δ = 2.19
(s, 3 H), 3.80 (s, 2 H), 3.82 (s, 3 H), 3.86 (s, 3 H), 5.39-5.56
(m, 2 H), 6.61 (d, J = 7.7 Hz,
1 H), 6.63 (s, 1 H), 6.68 (d, J = 3.2
Hz, 2 H), 6.82 (d, J = 7.7 Hz, 1
H). ¹³C NMR (100 MHz, CDCl3): δ = 19.2,
38.4, 55.8, 56.0, 111.1, 112.9, 114.1, 116.0, 121.3, 127.7, 132.0,
132.4, 143.3, 143.7, 144.6, 146.4. IR (KBr): 3384, 3022, 2931, 2835,
1608, 1513, 1460, 1431 cm-¹. MS (EI):
m/z
(%) = 274 (100) [M+],
273 (6), 259 (33), 150 (38). HRMS (EI): m/z calcd for C16H18O4:
274.1205; found: 274.1200.