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)
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)
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