Dienediolates of unsaturated carboxylic acids in synthesis. Synthesis of cyclohexenones and polycyclic ketones by tandem Michael-Dieckmann decarboxylative annulation of unsaturated carboxylic acids.
作者:María J. Aurell、Pablo Gaviña、Ramon Mestres
DOI:10.1016/s0040-4020(01)86973-8
日期:1994.2
Substituted 2-cyclohexenones 4 to 7 and hexaxydronaphthalenones and hexahydroindenones 13 to 18 are prepared by tandem Michael-Dieckmann addition of lithium dienediolates of acyclic and alicyclic unsaturated carboxylic acids to the lithium salts of the same or other unsaturated carboxylic acids.
1-Alkenyl cyclopropylketones, when activated by cation-stabilizing substituents at the ring carbon or at the terminal carbon of the enone moiety, undergo polyphosphoric acid-catalyzed ring enlargement producing cyclopentanone or cyclohexenone derivatives. Similar acid-catalyzed ring opening of 1-alkenyl 2-phenoxycyclopropyl ketones offers a convenient and effective synthesis of 4-oxo-5-alkenals and
Magnesium Chloride-Promoted Michael Addition of Dimethylsilyl Enolates to α-Enones
作者:Katsukiyo Miura、Akira Hosomi、Takahiro Nakagawa
DOI:10.1055/s-2003-41467
日期:——
In the presence of MgCl 2 , dimethylsilyl (DMS) enolates 1 smoothly reacted with α-enones in DMF to form1,5-diketones 3 in moderate to high yields. The Michael addition proceeded with moderate to high anti-diastereoselectivity.