| Identification | Back Directory | [Name]
1,3-Butadien-1-one, 2-(trimethylsilyl)- | [CAS]
75232-81-4 | [Synonyms]
2-(Trimethylsilyl)-1,3-butadien-1-one
1,3-Butadien-1-one, 2-(trimethylsilyl)- | [Molecular Formula]
C7H12OSi | [MOL File]
75232-81-4.mol | [Molecular Weight]
140.26 |
| Chemical Properties | Back Directory | [Boiling point ]
139.5±9.0 °C(Predicted) | [density ]
0.821±0.06 g/cm3(Predicted) | [solubility ]
sol CH2Cl2, CHCl3, CCl4, toluene, benzene, hexane,
most organic solvents. | [Appearance]
yellow-green liquid |
| Hazard Information | Back Directory | [Physical properties]
bp 49.0–50.5 °C/1.6 mmHg. | [Uses]
(Trimethylsilyl)vinylketene is reactive diene for [4 + 2] cycloadditions. | [Preparation]
Conveniently prepared as outlined in eq 1.
Treatment of 1-(trimethylsilyl)propyne (2)2 with 1.1 equiv of
diisobutylaluminum hydride (25??C, 21 h) and 1.1 equiv of
methyllithium (0??C, 0.5 h) in ether¨Chexane,2 followed by reaction of the resulting vinylalanate with anhydrous carbon
dioxide,3 yields (Z)-2-(trimethylsilyl)-2-butenoic acid (3) in
68% yield. Exposure of the potassium salt of this acid (4) to
1.1 equiv of oxalyl chloride in pentane containing a catalytic
amount of N,N-dimethylformamide (0¨C25??C, 1.5 h) then produced a mixture of the acid chloride (5) and its geometric isomer, which was dehydrohalogenated without further purification. A solution of (5) in pentane was added dropwise over
1¨C2 h to a solution of 0.9 equiv of triethylamine in pentane at 25??C, and the resulting mixture was heated at reflux for
15¨C24 h and then filtered with the aid of pentane. Solvent was
evaporated at ?50??C (0.5 mmHg), and the residue was distilled at 25??C (1 mmHg) and then again at 5 mmHg into a receiver cooled at ?78??C. In this manner a yellow-green liquid of
(trimethylsilyl)vinylketene (1) was obtained in 39¨C50% overall
yield (from 3).
| [storage]
purified vinylketenes can be stored under nitrogen in solution at 0 °C without appreciable decomposition for 1-2 weeks. |
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