A New Modulated Oxidative Ring Cleavage of α-Nitrocycloalkanones by Oxone®: Synthesis of α,ω-Dicarboxylic Acids and α,ω-Dicarboxylic Acid Monomethyl Esters
Michael Additions in Aqueous Media: “On-Water” and “In-Water” Processes from α-Nitro Ketones and Their Anions
作者:Giorgio Giorgi、Pilar López-Alvarado、Sonia Miranda、Jean Rodriguez、J. Carlos Menéndez
DOI:10.1002/ejoc.201201431
日期:2013.3
A variety of α,β-unsaturatedaldehydes and ketones gave very high-yielding Michael addition reactions with α-nitrocycloalkanones in water, at room temperature without added catalyst. These can be considered as one of the very few “on-water” Michael reactions known in the literature, because they took place in suspension or emulsion and at increased speed relative to the same transformations performed
Ring cleavage of 2-Nitrocycloalkanones with methanol/Amberlyst A 21 gave methyl Ï-nitroalkanoates, O2NCH2(CH2)nCO2Me where n = 3-6, 8-10, 13, in high yield. Subsequent Nef reaction gave the corresponding Ï-oxo compounds which were isolated, in the case of methyl 7-oxoheptanoate and methyl 8-oxooctanoate only, or reduced directly with sodium borohydride to give Ï-hydroxyalkanoates. A new formal synthesis of exaltolide (15-pentadecanolide) is also reported.
A novel reactivity of α-nitro ketone tosylhydrazones with DBU. Synthesis of α,β-unsaturated enone tosylhydrazones
作者:Roberto Ballini、Gianni Giantomassi
DOI:10.1016/0040-4020(95)00133-s
日期:1995.4
Treatment of α-nitro ketone tosylhydrazones with DBU gives 1,4-elimination of nitrous acid affording 1-tosylazoalkenes which, under basic conditions (DBU), tautomerize to the more stable enone tosylhydrazones. The obtained tosylhydrazones may be used as starting material for a wide range of other functionalities. Removal of the hydrazone affords conjugated enones in good yields. Due to the possibility
with aqueous 0.05 M NaOH, at 80 °C, in the presence of cetyltrimethylammonium chloride (CTACl) as a cationic surfactant, produces ω-nitro acids 2 in good yields. Reduction of the latter with HCOONH4/Pd-C, in methanol, at 80 °C affords ω-aminoacids 3. The synthesis of methyl 9-oxodecanoate (8) is also reported.
A General, Diastereoselective Synthesis of Highly Functionalized Bicyclo[n.3.1]alkane Systems Based on an Anionic Domino Reaction of α-Nitrocycloalkanones
作者:Giorgio Giorgi、Sonia Miranda、Miriam Ruiz、Jean Rodriguez、Pilar López-Alvarado、J. Carlos Menéndez
DOI:10.1002/ejoc.201001672
日期:2011.4
base-promoted Michael–aldol anionic domino reactions of cyclic α-nitro ketones and α,β-unsaturated aldehydes afforded bicyclo[n.3.1]alkanone systems of seven different ring sizes (n = 3–9), normally in excellent yields. This can be considered the first general method for the synthesis of this type of carbocycle. Furthermore, up to four stereocentres are generated, three of which are contiguous and include a functionalized