Development of the Juliá asymmetric epoxidation reaction. Part 2. Application of the oxidation to alkyl enones, enediones and unsaturated keto esters

Kroutil, Wolfgang; Lasterra-Sánchez, M. Elena; Maddrell, Samuel J.; Mayon, Patrick; Morgan, Philip E.; Roberts, Stanley M.; Thornton, Steven R.; Todd, C. J.; Tüter, Melek

doi:10.1039/p19960002837

Cited by 48 publications

(18 citation statements)

References 9 publications

(1 reference statement)

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“…Moreover, poly-D-leucine results in the optical isomer of the epoxide at a 98% yield and 93% ee (Table 5, entry 14). 234 Considering the insolubility of the polypeptide catalyst in toluene and water, a triphasic reaction system has also been used. Roberts and co-workers developed a nonaqueous phase method, where the aqueous H 2 O 2 −NaOH was replaced by urea−H 2 O 2 (UHP) and DBU.…”

Section: Chemical Reactions Related To Michael Acceptorsmentioning

confidence: 99%

Chalcone: A Privileged Structure in Medicinal Chemistry

et al. 2017

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Privileged structures have been widely used as an effective template in medicinal chemistry for drug discovery. Chalcone is a common simple scaffold found in many naturally occurring compounds. Many chalcone derivatives have also been prepared due to their convenient synthesis. These natural products and synthetic compounds have shown numerous interesting biological activities with clinical potentials against various diseases. This review aims to highlight the recent evidence of chalcone as a privileged scaffold in medicinal chemistry. Multiple aspects of chalcone will be summarized herein, including the isolation of novel chalcone derivatives, the development of new synthetic methodologies, the evaluation of their biological properties, and the exploration of the mechanisms of action as well as target identification. This review is expected to be a comprehensive, authoritative, and critical review of the chalcone template to the chemistry community.

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Section: Chemical Reactions Related To Michael Acceptorsmentioning

confidence: 99%

Chalcone: A Privileged Structure in Medicinal Chemistry

et al. 2017

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“…With both of the latter substrates, lower reaction rates and reduced selectivities were obtained in general, which can be attributed to the reduction of the alkyl chain length from n-butyl to ethyl, a phenomenon that has been noted before. [3] No significant influence of the halogen atom (Cl versus Br) on the stereoselectivity could be detected. The results obtained from trans-configured substrates 2a, 4a, 6a, and 8a (Table 2) show a different pattern.…”

Section: Resultsmentioning

confidence: 95%

“…[2] During our study of the asymmetric biohydrolysis of (Ϯ)-2,3-dialkyloxiranes by bacterial epoxide hydrolases, we discovered that (depending on the stereochemistry of the substrate) only single stereoisomers of the corresponding vicinal diols were formed, by enantioconvergent pathways and in 100% theoretical yield from the racemates. [3] In comparison with kinetic resolution, such ''deracemization'' processes show a considerably improved economic balance and thus have recently attracted considerable attention. [4] From previous studies, we knew that functional groups, as long as they are lipophilic, are tolerated well by bacterial epoxide hydrolases.…”

Section: Introductionmentioning

confidence: 99%

Enzyme-Triggered Enantioconvergent Transformation of Haloalkyl Epoxides

Mayer¹,

Steinreiber²,

Orru³

et al. 2001

Eur. J. Org. Chem.

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Biocatalytic hydrolysis of 2,3‐disubstituted rac‐cis‐ and rac‐trans‐haloalkyl epoxides 1a−8a using the epoxide hydrolase activity of whole bacterial cells furnished the corresponding vicinal diols 1b−8b as intermediates; these (spontaneously) underwent ring closure to yield cyclic products 1c−6c through an enzyme‐triggered cascade reaction. In particular, cis‐configured substrates (1a, 3a, 5a, 7a) were transformed in an enantioconvergent fashion, which resulted in the formation of single stereoisomeric products in 100% des and up to 92% ees from the racemates.

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“…The asymmetric WeitzϪScheffer epoxidation of the α,β-enones 1 with the optically active hydroperoxides 2, catalyzed by KOH or DBU, affords both enantiomers of the epoxides 3 with ee values that range up to good, which should be valuable for asymmetric organic synthesis. 13 C: 63 MHz) spectrometers, IR spectra were measured with a PerkinϪElmer 1600 FT-IR spectrophotometer. The HPLC analyses were carried out on chiral columns (Daicel CHIRALCEL OD and OB-H) with a Kontron instrument, furnished with a UVIKON 720 spectrophotometer and an IBZ Massetechnik (Hannover, Germany) CHIRALYSER 1.6.…”

Section: Resultsmentioning

confidence: 99%

Asymmetric Weitz−Scheffer Epoxidation of α,β-Enones by Optically Active Hydroperoxides: Control of Enantioselectivity through Metal-Coordinated or Hydrogen-Bonded Templates

et al. 2002

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The enantioselective epoxidation of the α,β-enones 1 with the optically active hydroperoxides (−)-(S)-2, catalyzed by the bases KOH or DBU, affords the enantiomerically enriched oxo epoxides 3 in high yields and with good enantioselectivities (up to 90% ee for KOH and up to 72% ee for DBU). The preparatively useful feature of this asymmetric epoxidation is the fact that opposite senses of enantioselectivity are observed with the same optically active hydroperoxide and the same prochiral enone substrate. Thus, whereas KOH in CH 3 CN affords the (αS,βR)-epoxide 3a from chalcone 1a, [a]

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Development of the Juliá asymmetric epoxidation reaction. Part 2. Application of the oxidation to alkyl enones, enediones and unsaturated keto esters

Cited by 48 publications

References 9 publications

Chalcone: A Privileged Structure in Medicinal Chemistry

Chalcone: A Privileged Structure in Medicinal Chemistry

Enzyme-Triggered Enantioconvergent Transformation of Haloalkyl Epoxides

Asymmetric Weitz−Scheffer Epoxidation of α,β-Enones by Optically Active Hydroperoxides: Control of Enantioselectivity through Metal-Coordinated or Hydrogen-Bonded Templates

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