- A new, highly efficient synthesis of conjugated nitrocycloalkenes
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Sodium borohydride reduction of α-nitrocycloalkanones and successive dehydration of the obtained β-nitroalkanols, by acetylation and dehydroacetylation with basic alumina/DMAP, in refluxing dichloromethane, affords, in one por procedure, conjugated nitrocycloalkenes.
- Ballini, Roberto,Palestini, Corrado
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p. 5731 - 5734
(2007/10/02)
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- α-Nitro Keto Hydrazone and Keto Imine Dianions. Synthetic Equivalents for the Nitroalkene d3 Synthon
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A general method for the preparation of 3-substituted nitrocycloalkenes has been developed. 2-Nitrocycloalkanones are transformed into iether α-nitro N,N-dimethylhydrazones or α-nitro cyclohexylimines, which exist exclusively in the aci-nitro form.Double deprotonation of these materials with sec-BuLi produces higly reactive dianions which can by alkylated with methyl, allyl, n-butyl, isopropyl, or 4-hexenyl iodides in excelent yields.The alkylation occurred uniformly next to the hydrazone or imine function.The alkylated α-nitro hydrazones are converted to nitroalkenes by reduction with NaBH4 followed by elimination induced by heating (120 deg C) with acetic anhydride.The alkylated α-nitro imines undergo facile reduction-elimination with NaBH4/CeCl3 ar room temperature.The overal yield for 2-nitro ketone to nitroalkene transformation ranged from 35percent to 44percent for the hydrazone method and from 19percent to 39percent for the imine method.
- Denmark, Scott E.,Sternberg, Jeffrey A.,Lueoend, Rainer
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p. 1251 - 1263
(2007/10/02)
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- α-NITRO KETONES 7 : SYNTHESIS OF CONJUGATED NITROCYCLOHEXENES
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The reduction of 2-nitrocyclohexanones to the 2-nitrocyclohexanols with sodium borohydride followed by treatment of the β-nitroalcohols with sodium hydride and subsequent acidification of the salts leads to the regioselective synthesis of conjugated nitrocyclohexenes from cyclohexanones.
- Dampawan, Pimchit,Zajac, Walter W.
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p. 135 - 138
(2007/10/02)
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