Multicomponent asymmetric reactions mediated by proline lithium salt
作者:Polyssena Renzi、Jacob Overgaard、Marco Bella
DOI:10.1039/b924158b
日期:——
The multicomponent reaction between proline lithium salt, 2-cyclohexen-1-one and aliphatic aldehydes affords the 4-alkylidene-2-cyclohexen-1-ones, which are interesting fragrances, and bicyclic amino acids that bear four additional stereocenters, obtained as single stereoisomer.
The anionic and the cationic partners of ionic liquids may act cooperatively and independently as nucleophilic and electrophilic catalysts. This ambiphilic propensity was demonstrated by kinetically discriminating the contributions of the anion (nucleophilic catalyst) and of the cation (electrophilic catalyst) to the solvent-free BaylisâHillman dimerization of cyclohexenone catalysed by ionic liquids.
An Efficient Organocatalytic Method for Highly Enantioselective Michael Addition of Malonates to Enones Catalyzed by Readily Accessible Primary Amine-Thiourea
作者:Krzysztof Dudziński、Anna M. Pakulska、Piotr Kwiatkowski
DOI:10.1021/ol3019055
日期:2012.8.17
A practical and highlyenantioselectiveMichaeladdition of malonates to enones catalyzed by simple and readily available bifunctional primary amine-thiourea derived from 1,2-diaminocyclohexane is reported. The addition of weak acids and elevated temperature (ca. 50 °C) improved the efficiency of the Michael reaction. This approach enables the efficient synthesis of 1,5-ketoesters with good yields
Simple method for α-alkylation of α,β-unsaturated enones through the Michael addition
作者:Ru Hwu Jih、Gholam H. Hakimelahi、Ching-Tai Chou
DOI:10.1016/s0040-4039(00)79017-4
日期:1992.10
Treatment of enones and Michael acceptors with a catalytic amount of 1,8-diazabicyclo[5.4.0]undec-7-ene in 1,3-dimethyl-2-imidazolidinone at 185 °C afforded the corresponding α-substituted enones in good yields.
Hydroxy Chalcogenide-Promoted Morita-Baylis-Hillman Alkylation Reaction: Intermolecular Applications with Alkyl Halides as Electrophiles
作者:Ana Gradillas、Efres Belmonte、Rondes Ferreira da Silva、Javier Pérez-Castells
DOI:10.1002/ejoc.201301743
日期:2014.3
Hydroxysulfides acted as catalysts to promote the Morita–Baylis–Hillmanalkylationreaction of cyclohexenones and dihydropyridinones. The procedure worked efficiently with a variety of halides as electrophiles. Side reactions were in competition with the MBH alkylation, but fine-tuning the reaction conditions minimized their occurence.