Asymmetric C–C bond forming reactions with chiral crown catalysts derived from d-glucose and d-galactose

Bakó, Péter; Czinege, Erzsebet; Bakó, Tibor; Czugler, Mátyás; Tőke, Lásʐló

doi:10.1016/s0957-4166(99)00485-1

Cited by 90 publications

(45 citation statements)

References 28 publications

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“…The addition of 2-nitropropane (10) to trans-chalcone (9) was carried out in toluene, in the presence of solid sodium tert-butoxide (35 mol%) using one of the chiral catalysts (7 mol%) prepared by us as reported previously 16,45 (Scheme 2).…”

Section: Resultsmentioning

confidence: 99%

“…26,27 Stoddart performed pioneering work in preparing and investigating macrocycles built up from sugar alcohols such as L-iditol, L-threitol, and D-mannitol. [15][16][17]26,27 At that time, they had not yet studied the catalytic effects of these compounds in phase transfer reactions. Later on, a few articles were published on the synthesis of chiral crown ethers derived from diethyl L-tartrate, [28][29][30][31][32][33][34][35][36][37] but from among the macrocycles prepared, only a few were investigated as chiral phase transfer catalysts, which were not too efficient.…”

Section: -13mentioning

confidence: 99%

“…were synthesized. [15][16][17] A few of them proved to be efficient phase transfer catalysts in certain asymmetric reactions. …”

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confidence: 99%

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Synthesis of l‐threitol‐based crown ethers and their application as enantioselective phase transfer catalyst in Michael additions

et al. 2017

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A few new l-threitol-based lariat ethers incorporating a monoaza-15-crown-5 unit were synthesized starting from diethyl l-tartrate. These macrocycles were used as phase transfer catalysts in asymmetric Michael addition reactions under mild conditions to afford the adducts in a few cases in good to excellent enantioselectivities. The addition of 2-nitropropane to trans-chalcone, and the reaction of diethyl acetamidomalonate with β-nitrostyrene resulted in the chiral Michael adducts in good enantioselectivities (90% and 95%, respectively). The substituents of chalcone had a significant impact on the yield and enantioselectivity in the reaction of diethyl acetoxymalonate. The highest enantiomeric excess (ee) values (99% ee) were measured in the case of 4-chloro- and 4-methoxychalcone. The phase transfer catalyzed cyclopropanation reaction of chalcone and benzylidene-malononitriles using diethyl bromomalonate as the nucleophile (MIRC reaction) was also developed. The corresponding chiral cyclopropane diesters were obtained in moderate to good (up to 99%) enantioselectivities in the presence of the threitol-based crown ethers.

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Section: Resultsmentioning

confidence: 99%

Section: -13mentioning

confidence: 99%

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Synthesis of l‐threitol‐based crown ethers and their application as enantioselective phase transfer catalyst in Michael additions

et al. 2017

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“…The methyl-α-D-glucopyranoside-based lariat ether 1 synthetized by us earlier 19 was found to be an efficient enantioselective catalyst in the addition of diethyl malonate and α-substituted diethyl malonates to trans-chalcones and cyclic enones.…”

Section: Resultsmentioning

confidence: 99%

Crown ether derived from d-glucose as an efficient phase-transfer catalyst for the enantioselective Michael addition of malonates to enones

Rapi

Grűn

Nemcsok

et al. 2016

Tetrahedron: Asymmetry

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A monoaza-15-crown-5 lariat ether derived from D-glucose (1) has been applied as chiral phase-transfer catalyst in the Michael addition of diethyl, dimethyl, diisopropyl and dibenzyl malonates to enones under mild conditions to afford the adducts in good to excellent enantioselectivities. In the reaction of diethyl malonate with substituted trans-chalcone, the adducts formed in enantioselectivities up to 89% ee. Among the reactions of substituted diethyl malonates, that of diethyl acetoxymalonate gave the best results (96% ee). The effect of the substituents of the chalcone was also investigated in reaction with diethyl acetoxymalonate. Among the chalcones substituted on the β side, the para-substituted compounds resulted in the highest enantioselectivities (88-97% ee). The substituents on the α-side of chalcone caused a decrease in the enantioselectivity, as compared to the unsubstituted case. The adducts having furyl or thiophenyl substituents were formed with >99% ee. The glucose-based catalyst also proved to be effective in the cases of diisopropyl and dibenzyl acetoxymalonates (including ee-s up to 99% ee). The reactions of diethyl acetoxymalonate with cyclic enones gave the corresponding Michael adducts in enantioselectivities up to 83%.-2 -The absolute configuration of one of the new Michael adducts was determined by CD spectroscopy.

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“…More recently Toké's group has used catalytic chiral aza crown ethers in Darzens reactions [40][41][42], but again only low to moderate enantioselectivities resulted. [44] to a range of alkyl and aromatic aldehydes [45] and also obtained moderate selectivities on treatment of chlorosulfone 93 with aromatic aldehydes (Entries 7-9) [46,47].…”

Section: Darzens Reactions With Chiral Catalystsmentioning

confidence: 99%

Asymmetric Synthesis of Epoxides and Aziridines from Aldehydes and Imines

Aggarwal¹,

Badine²,

Moorthie³

2006

Aziridines and Epoxides in Organic Synthesis

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Epoxides and aziridines are strained three-membered heterocycles. Their synthetic utility lies in the fact that they can be ring-opened with a broad range of nucleophiles with high or often complete stereoselectivity and regioselectivity and that 1,2-difunctional ring-opened products represent common motifs in many organic molecules of interest. As a result of their importance in synthesis, the preparation of epoxides and aziridines has been of considerable interest and many methods have been developed to date. Most use alkenes as precursors, these subsequently being oxidized. An alternative and complementary approach utilizes aldehydes and imines. Advantages with this approach are: i) that potentially hazardous oxidizing agents are not required, and ii) that both C-X and C-C bonds are formed, rather than just C-X bonds (Scheme 1.1).This review summarizes the best asymmetric methods for preparing epoxides and aziridines from aldehydes (or ketones) and imines. Asymmetric Epoxidation of Carbonyl CompoundsThere have been two general approaches to the direct asymmetric epoxidation of carbonyl-containing compounds (Scheme 1.2): ylide-mediated epoxidation for the construction of aryl and vinyl epoxides, and a-halo enolate epoxidation (Darzens reaction) for the construction of epoxy esters, acids, amides, and sulfones.

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Asymmetric C–C bond forming reactions with chiral crown catalysts derived from d-glucose and d-galactose

Cited by 90 publications

References 28 publications

Synthesis of l‐threitol‐based crown ethers and their application as enantioselective phase transfer catalyst in Michael additions

Synthesis of l‐threitol‐based crown ethers and their application as enantioselective phase transfer catalyst in Michael additions

Crown ether derived from d-glucose as an efficient phase-transfer catalyst for the enantioselective Michael addition of malonates to enones

Asymmetric Synthesis of Epoxides and Aziridines from Aldehydes and Imines

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