The reaction of the dianion of β-enaminoketones with electrophiles. Part 6. Synthesis of γ′- and ε-nitro-β-enaminoketones.

✍ Scribed by Giuseppe Bartoli; Marcella Bosco; Renato Dalpozzo; Antonio De Nino; Gianni Palmieri

• Book ID: 104203358
• Publisher: Elsevier Science
• Year: 1994
• Tongue: French
• Weight: 499 KB
• Volume: 50
• Category: Article
• ISSN: 0040-4020
• DOI: 10.1016/s0040-4020(01)85548-4

✦ Synopsis

a'-And y-dianions of acyclic p-(monoalkylamino)-a$-unsaturated ketones can attack the double bond of nitroalkenes affording y-and a-nitro-benaminoketones in good to high yields. In contrast to the corresponding 1,3dicarbonyl dianions, cyclic products from intramolecular Hemy reactions are never observed. Quenching the reaction with sulphuric acid a-nitro-&enaminoketones are converted in low yields into dihydmpynoles. Dianions of acylic P_(monoslkylamino)-u,~unsaturated ketones have been revealed the comerstone of the regiocontrolled attack at the a'-and rpositions of unsymmetrical 1,3dicarbonylsr. Appropde generation tecniques allow the almost exclusive formation of the a' or the y dianion (scheme l), which reacts with a large variety of electrophiles such as alkyl halidest. oxirancs~, nitriless. es&&, aldehydes and ketoness, leading to both straight chain and heterocyclic products. Scheme 1 MeLiiA 1 3

These results prompted us to investigate the reaction with nitroalkenes. The inuoduction of a nitro group in the all@ side chain would incmase the synthetic utility of these reactions since it may be transformed in a legion of diverse functionality such as carbonyl derivatives, oxitr~, amines, nitrile oxides or carboxylic a&#.