2.2.2-Propellane

Chemical compound bracket omission [2.2.2]Propellane changed changed 418039735 [2.2.2]Propellane 2.2.2-propellane.svg 2.2.2-propellane.png 150px Tricyclo[2.2.2.01,4]octane 36120-88-4 correct ?? correct FDA N79VJK4GSD 564666 changed chemspider 490864 C1C23C(CC2)(CC3)C1 1/C8H12/c1-2-8-5-3-7(1,8)4-6-8/h1-6H2 GPMHXZWOEIWUPW-UHFFFAOYAI changed chemspider 1S/C8H12/c1-2-8-5-3-7(1,8)4-6-8/h1-6H2 changed chemspider GPMHXZWOEIWUPW-UHFFFAOYSA-N 8 12 [2.2.2]Propellane, formally tricyclo[2.2.2.01,4]octane is an organic compound, a member of the propellane family. It is a hydrocarbon with formula C8H12, or C2(C2H4)3. Its molecule has three rings with four carbon atoms each, sharing one C–C bond. This compound is unstable (although not as much as [1.1.1]propellane; however it is less persistent than [1.1.1]propellanehttps://www.thieme.de/shop/Houben-Weyl--SoS/de-Meijere-Butenschoen-Chow-Fitjer-Haufe-Houben-Weyl-Methods-of-Organic-Chemistry-9783131819840/p/000000009583004404 https://web.archive.org/web/20171022033632/https://www.thieme.de/shop/Houben-Weyl--SoS/de-Meijere-Butenschoen-Chow-Fitjer-Haufe-Houben-Weyl-Methods-of-Organic-Chemistry-9783131819840/p/000000009583004404 dead October 22, 2017 Houben-Weyl Methods of Organic Chemistry Vol. E 17e, 4th Edition Supplement (E-Book PDF) - Thieme.de - Thieme Webshop - Armin de Meijere, Holger Butenschön, Hak-Fun Chow, Lutz Fitjer, Günter Haufe Thieme Webshop de 2017-10-21). The bond angles on the shared carbons are considerably strained: three of them are close to 90°, the other three to 120°. The strain energy is estimated to be 93 kcal/mol (390 kJ/mol). Synthesis [2.2.2]Propellane was first synthesized in 1973 by the group of Philip Eaton (who had earlier obtained cubane),Philip E. Eaton George H. Temme Philip Eaton 1973 [2.2.2]Propellane system J. Am. Chem. Soc. 95 22 7508–7510 10.1021/ja00803a052 according to the following scheme: thumb|none|400px|Synthesis of the [2.2.2]propellane skeleton. The synthesis begins with photochemical [2+2]cycloaddition of ethene on the cyclohexene derivative 1 to produce the bicyclic compound 2, followed by elimination reaction with potassium t-butoxide of acetic acid to cyclobutene 3, followed by another cycloaddition with ethylene to 4. This compound is converted to the diazo ketone 5 by deprotonation (using acetic acid and sodium methoxide) and reaction with tosyl azide. The ketone then undergoes Wolff rearrangement to ketene 6. Ozonolysis forms the ketone 7, another diazotation yields the diazo ketone 8, which undergoes Wolff rearrangement again to the ketene 9. Reaction with dimethylamine affords the [2.2.2]propellane backbone with a dimethylamide substituent 10. The final product 10 was found to spontaneously isomerize in solution to the monocyclic amide 11, with a half-life of 28 minutes at room temperature. See also [1.1.1]Propellane Triptycene References Category:Tricyclic compounds Category:Cyclobutanes Category:Substances discovered in the 1970s