Stereoselective Synthesis of Optically Active b-Lactams by the Reaction of Chiral Imines Derived from erythro-2-Amino-1,2-diphenylethanol with Ester Enolates

Hashimoto, Yukihiko; Ogasawara, Tsuneo; Hayashi, Minoru; Saigo, Kazuhiko

doi:10.3987/com-99-s95

Cited by 10 publications

(4 citation statements)

References 6 publications

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“…Amine-free lithium enolates can be obtained by treating silylketene acetals with MeLi. The reaction of the lithium enolates with a chiral imine afforded the corresponding β-lactams with high diastereoselectivity, which was rationalized by the formation of the transition state 461 (Scheme ) …”

Section: Azetidin-2-onesmentioning

confidence: 99%

“…The reaction of the lithium enolates with a chiral imine afforded the corresponding β-lactams with high diastereoselectivity, which was rationalized by the formation of the transition state 461 (Scheme 124). 210 Also, lithium acetate or methoxide, N-lithio-2-pyrrolidone, potassium phtalimide, 211 and tris(2,4,6-trimethoxyphenyl)phosphine 212 were revealed to be proper Lewis bases for the Mannich-type addition and cyclization of aldimines and ketenesilyl acetals (Scheme 125). Mixtures of β-lactams 464 with the corresponding β-aminoester were obtained, but usually the β-lactam is the main product, and in some cases the only one.…”

Section: Enolate-imine Condensation 199mentioning

confidence: 99%

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Novel Syntheses of Azetidines and Azetidinones

2008

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Primary amines reacted upon 4,6-ditosylates of glucopyranosides 47 to give compounds 48a,c, with an azetidine ring formed between C4 and C6 of the pyranose ring, in good yields. Interestingly, corresponding mannopyranosides led to the uncyclized 4,6-diamino-4,6-dideoxy compounds (Scheme 13). 11f An azetidine isostere 52 of the oxetane-type taxane 1-deoxy-2-debenzoyloxy-4-deacetylbaccatin VI was synthesized starting from the alkaloid 2′-deacetoxyaustrospicatine 49 (Scheme 14). 10i Scheme

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Section: Azetidin-2-onesmentioning

confidence: 99%

Section: Enolate-imine Condensation 199mentioning

confidence: 99%

Novel Syntheses of Azetidines and Azetidinones

2008

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“…The asymmetric induction in the reaction of achiral ketenes with chiral imines has been effected from imines derived from chiral aldehydes and achiral amines and also from imines derived from chiral amines and achiral aldehydes [1][2][3][4][5][6]. Hashimoto and his coworkers have used chiral imines derived from erythro 2-methoxy-1,2-diphenylethylamine and aromatic aldehydes to prepare β-lactams in good yields with high diastereoselectivity [7]. Recently high levels of asymmetric induction has also been reported for monocyclic β-lactam formation [8][9].…”

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confidence: 99%

Asymmetric Synthesis of a New Monocyclic β-Lactam as a potential biological active compound

Jarrahpour

Jahaniani

2005

Molbank

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“…High levels of asymmetric induction in reactions between Evans-Sjogren ketenes and imines derived from (R)-and (S)-α-amino acid esters have been reported [8]. Hashimoto and his coworkers have used chiral imines derived from erythro 2-methoxy-1,2-diphenylethylamine and aromatic aldehydes to prepare β-lactams in good yields with high diastereoselectivity [9]. Recently, high levels of asymmetric induction have also been reported for monocyclic β-lactam formation [10][11].…”

Section: Introductionmentioning

confidence: 99%

Asymmetric Synthesis and Antimicrobial Activity of Some New Mono and Bicyclic β-Lactams

Jarrahpour

Shekarriz

Taslimi³

2004

Molecules

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Abstract:Reaction of the amino acid D-phenylalanine ethyl ester (4) with cinnamaldehyde gave chiral Schiff base 5, which underwent an asymmetric Staudinger [2+2] cycloaddition reaction with phthalimidoacetyl chloride to give the monocyclic β-lactam 6 as a single stereoisomer. Ozonolysis of 6 followed by reduction with lithium aluminum tri(tert-butoxy) hydride afforded the hydroxymethyl β-lactam 8. Treatment of 8 with methansulfonyl chloride gave the mesylated monocyclic β-lactam 9, which was converted to the bicyclic β-lactam 10 upon treatment with 1,8-diazabicyclo[5,4.0] undec-7-ene (DBU). Deprotection of the phthalimido group in β-lactams 6 and 10 by methylhydrazine and subsequent acylation of the free amino β-lactams with different acyl chlorides in the presence of pyridine afforded mono and bicyclic β-lactams 14a-d and 15a-d respectively. The compounds prepared were tested against Escherichia coli, Staphilococcus citrus, Klebsiella pneumanie and Bacillus subtillis. Some of these compounds showed potential antimicrobial activities.

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Stereoselective Synthesis of Optically Active b-Lactams by the Reaction of Chiral Imines Derived from erythro-2-Amino-1,2-diphenylethanol with Ester Enolates

Cited by 10 publications

References 6 publications

Novel Syntheses of Azetidines and Azetidinones

Novel Syntheses of Azetidines and Azetidinones

Asymmetric Synthesis of a New Monocyclic β-Lactam as a potential biological active compound

Asymmetric Synthesis and Antimicrobial Activity of Some New Mono and Bicyclic β-Lactams

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