Direct Intramolecular Conjugate Addition of Simple Alkenes to α,β-Unsaturated Carbonyls Catalyzed by Cu(OTf)<sub>2</sub>
作者:Yan Qin、Jian Lv、Sanzhong Luo、Jin-Pei Cheng
DOI:10.1021/ol502373u
日期:2014.10.3
An unprecedented intramolecular conjugate addition of simple alkenes to α,β-unsaturated carbonyl compounds has been developed. A simple Lewis acid such as Cu(OTf)2 was found to effectively catalyze the reaction, and six- and five-membered cyclic products were obtained in moderate to high yields.
Diastereo- and enantioselective direct vinylogous Michael addition of γ-substituted butenolides to 2-enoylpyridines catalyzed by chiral bifunctional amine-squaramides
The diastereo- and enantioselectivedirectvinylogousMichaeladdition reaction of [gamma]-substituted butenolides to 2-enoylpyridines has been achieved. A range of [gamma],[gamma]-disubstituted butenolide derivatives, bearing two consecutive tri- and tetrasubstituted stereogenic...
Efficient and Highly Enantioselective Construction of Trifluoromethylated Quaternary Stereogenic Centers via High-Pressure Mediated Organocatalytic Conjugate Addition of Nitromethane to β,β-Disubstituted Enones
A very effective high-pressure-induced acceleration of asymmetric organocatalyticconjugateaddition of nitromethane to sterically congested β,β-disubstituted β-CF3 enones has been developed. A combination of pressure (8–10 kbar) and noncovalent catalysis with low-loading of chiral tertiary amine-thioureas (0.5–3 mol %) is shown to provide very efficient access to a wide range of γ-nitroketones containing
Enantioselective synthesis of benzoindolizidine derivatives using chiral phase-transfer catalytic intramolecular domino aza-Michael addition/alkylation
作者:Jiajia Guo、Shouyun Yu
DOI:10.1039/c4ob02227k
日期:——
An efficient and enantioselective strategy to synthesize benzoindolizidines from alpha,beta-unsaturated amino ketones via domino intramolecular aza-Michael addition/alkylation was developed. These reactions were enabled by cinchona alkaloid-derived quaternary ammonium salts as the phase-transfer catalyst. A variety of benzoindolizidines were prepared in good yields (up to 93%) and enantioselectivities
Synthesis and properties of tungsten(0) carbonyl complexes with carbonyl-stabilized ylides
作者:Isao Kawafune、Gen-Etsu Matsubayashi
DOI:10.1016/s0020-1693(00)82769-3
日期:1983.1
The reactions of dimethylsulfonium, triphenylphosphonium, and 4-methylpyridinium phenacylides (PhC(O)CHZ+; Z+ = S+Me2 (Y Ph-S) P+Ph3 (Y Ph-P, and N+C5H4Me-4 (Y Ph-N)) with W(CO)5THF gave W(CO)5(PhC(O)CHZ+. IR and 1H NMR spectra have indicated the ylide carbon-to-tungsten linkage in W(CO)5YPh-S and the coordination of the carbonyl oxygen atom in W(CO)5YPh-P and W(CO)5YPh-N. The corresponding three