A Chiral Electrophilic Selenium Catalyst for Highly Enantioselective Oxidative Cyclization
Chiral electrophilic selenium catalysts have been applied to catalytic asymmetric transformations of alkenes over the past two decades. However, highly enantioselective reactions with a broad substrate scope have not yet been developed. We report the first successful example of this reaction employing a catalyst based on a rigid indanol scaffold, which can be easily synthesized from a commercially available indanone. The reaction efficiently converts β,γ-unsaturated carboxylic acids into various enantioenriched γ-butenolides under mild conditions.
Kawamata, Yu,Hashimoto, Takuya,Maruoka, Keiji
p. 5206 - 5209
(2016/05/19)
Synthesis of chiral butenolides using amino-thiocarbamate-catalyzed asymmetric bromolactonization
The asymmetric cyclization of 4,4-disubstituted 3-butenoic acids is studied. Amino-thiocarbamates are used as the catalysts and N-bromosuccinimide is used as the stoichiometric halogen source. The resulting γ-butanolide products are readily converted into the corresponding γ-butenolides (up to 58% ee) derivatives in one-pot.
Tan, Chong Kiat,Er, Jun Cheng,Yeung, Ying-Yeung
p. 1243 - 1246
(2014/02/14)
A facile solid-phase synthesis of substituted 2(5H)-furanones with sulfone traceless linker
A novel solid-phase synthetic method for substituted 2(5H)-furanones with traceless sulfone linker strategy has been developed. The products were obtained in good yields and excellent purities.
Enantiodivergent syntheses of γ-substituted butenolides with tertiary and quaternary asymmetric centers
Continuous nucleophilic addition with several organometallic reagents to tricyclic lactone (-)-1 proceeded diastereoselectively. Newly generated tertiary and quaternary asymmetric centers were controlled by the order in which the nucleophilic reagents were added. Using this methodology, enantiodivergent syntheses of several γ-substituted butenolides with tertiary and quaternary asymmetric centers were established from a single chiral material.
Suzuki, Katsufumi,Inomata, Kohei
p. 745 - 749
(2007/10/03)
A convergent asymmetric synthesis of γ-butenolides
The addition of aldehydes to the new enantiomerically pure lithiated sulfoxide-orthoester 13 yielded γ-butenolides of high enantiomeric purities after elimination of phenylsulfinic acid. The cyclocondensation with ketones was less stereoselective. This new asymmetric synthesis of γ-butenolides has been applied to a convergent preparation of the antifungal antibiotic (+)-cerulenin.
Renard, Marc,Ghosez, Léon A.
p. 2597 - 2608
(2007/10/03)
A convergent asymmetric synthesis of γ-butenolides
Addition of aldehydes to the new enantiomerically pure lithiated sulfoxide 4 yielded γ-butenolides of high enantiomeric purities after elimination of phenylsulfinic acid. The reaction with ketones was less stereoselective.
Renard, Marc,Ghosez, Leon
p. 6237 - 6240
(2007/10/03)
145. Analytic and Preparative Resolution on Racemic γ- and δ-Lactones by Chromatography on Cellulose Triacetate. Relationship between Elution Order and Absolute Configuration
Enantiomers of various chiral five- and six-membered-ring lactones, which are important classes of cpmpounds (flavour and pheromone components, key intermediates in the synthesis of biologically active substrates) have been separated chromatographically on the chiral phase cellulose triacetate, crystallographic form I (CTA I).Four different series of five-membered-ring lactones, relationships have been found between the elution order of the enantiomers and their absolute configuration.Preparative resolutions of γ-phenyl-γ-butyrolactone (1) and of the pheromone component 5b have been carried out to demonstrate the applicability of the method to g-scale separations.
Francotte, Eric,Lohmann, Dieter
p. 1569 - 1582
(2007/10/02)
Synthesis of Both Enantiomers of Optically Pure Saturated and α,β-Unsaturated γ-Substituted γ-Lactones from Chiral Sulphoxides. X-Ray Molecular structure of (3R,4S)-4-Methyl-4-t-butyl-3-(p-tolylthio)butanolide and of (3R,4R)-4-(Cyclohex-1-enyl)-4-methyl-3
The lithium carbanions of optically pure (+)-(R)-p-tolyl alkyl sulphoxides (5) reacted with lithium bromoacetate and gave (+)-(R)-3-(p-tolylsulphinyl)carboxylic acids (3).Their dimetallation produced a chiral homoenolate dianion equivalent (6) which added
Chiral Homoenolate Anion Equivalents: Synthesis of Optically Pure 5-Substituted Furan-2(5H)-ones
Addition of the dianion of (+)-(R)-3-propionic acid (1) to aldehydes affords two main diastereoisomeric β-sulphinyl-γ-lactones, pyrolysis of which gives the two enantiomers of 5-substituted furan-2(5H)-ones in optically pure for