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Tandem cyclization/ sigmatropic rearrangement of a-3-nitropropyl-1-cyclohexene-1-methanol derivatives
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http://hdl.handle.net/1860/3794
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| Title: | Tandem cyclization/ sigmatropic rearrangement of a-3-nitropropyl-1-cyclohexene-1-methanol derivatives |
| Authors: | Kotowich, Steven |
| Keywords: | Chemistry
Sigmatropic rearrangement
Tandem cyclization |
| Issue Date: | May-2012 |
| Abstract: | In this investigation the focus is on the formation of nitro compounds via sigmatropic rearrangement of 0-allyl nitronic esters. a-[3-Nitropropyl]-1-cyclohexene-1-methanol and two derivatives were prepared by Michael additions of 1-(1-cyclohexen-1-yl)-2- propen-1-one with appropriate substituted nitro compounds. The Michael adducts of nitromethane, ethyl nitroacetate, and phenylsulfonyl nitromethane were prepared in yields of74-76%. Reduction of the ketone carbonyl group ofthe Michael adducts with NaBH4 afforded a-[3-nitropropyl]-1-cyclohexene-1-methanol and two of its derivatives, one substituted with a carboethoxy group and the second with a phenylsulfonyl group in yields of79-81%. Cyclization ofthese nitroalcohols was attempted using DEAD and triphenylphosphine. Only the carboethoxy derivative afforded an identifiable product. Ethyl-1-nitro-1,2,3,5,6,7,8,8a-octahydro-1-naphthalene carboxylate was obtained as the
product of this reaction in 48% yield and an 90:10 diastereomer ratio. Apparently, this product arises from cyclization of the nitroalcohol to give the corresponding 0-allyl nitronic ester, which then rearranges in situ to the y,£5unsaturated nitro compound. Both possible diastereomers of the product were formed but one was major. Both possible diastereomers were also obtained by an alternate synthesis. Thus Diels Alder cyclization of ethyl 2-nitro-2-propenoate and 1-ethenylcyclohexene gave ethyl 1-nitro-1,2,3,5,6,7,8,8a-octohydro-1-naphthalene carboxylate, as an 72:25 mixture oftwo isomers. The major isomer corresponds to the major isomer prepared by the DEAD cyclization route. |
| Description: | Thesis (PhD, Chemistry)--Drexel University, 2012. |
| URI: | http://hdl.handle.net/1860/3794 |
| Appears in Collections: | Drexel Theses and Dissertations
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