Stereochimie en serie β-lactame : Stereochimie de la reaction de reformatzky sur les bases de schiff

Kagan, Henri B.; Basselier, Jean-Jacques; Luche, Jean‐Louis

doi:10.1016/s0040-4039(00)90411-8

Cited by 79 publications

(17 citation statements)

References 9 publications

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“…P-Lactam 2 appeared to be one compound, since it and all substances derived froni it travelled as one spot on tlc, using different systems, and since its 'Hmr spectrum and that of all compounds derived from it-never indicated the presence of more than one isomer. The coupling constant of the two hydrogens attached to the p-lactam ring indicated in all cases in which they did not seriously overlap with other signals that the fusion was cis (J = 5.5 Hz (7,8)). The geometry at C-1 will be discussed later, as well as the fact that all p-lactams formed were racemic.…”

mentioning

confidence: 86%

The synthesis of D,L-cis-N-oxalamido-3-N-phenylacetamido-4-methoxy methyl-2-azetidinone

Just¹,

Liak²

1978

Can. J. Chem.

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confidence: 86%

The synthesis of D,L-cis-N-oxalamido-3-N-phenylacetamido-4-methoxy methyl-2-azetidinone

Just¹,

Liak²

1978

Can. J. Chem.

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“…Geometry of the silyl ketene acetal did not influence the diastereoisomeric ratio because (E)-and (Z)-1-[(ethylthio)prop-1-enyloxy] trimethylsilane afforded the b-aminothioester with same syn/anti ratios (Table 13, entries 8 and 9). The relative stereochemistry was confirmed by base-cyclization to the corresponding b-lactam and comparison of the vicinal proton-proton coupling constants with those in the literature (Scheme 11) [112,113].…”

Section: Bismuth-mediated Three-component Mannich-type Reactionmentioning

confidence: 63%

Bismuth-Catalyzed Addition of Silyl Nucleophiles to Carbonyl Compounds and Imines

Ollevier

2011

Bismuth-Mediated Organic Reactions

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Bismuth triflate was found to be an efficient catalyst both in the Mannich-type reaction of silyl enolates and in the Sakurai reaction of allyltrimethylsilane with N-alkoxycarbonylamino sulfones. The reactions proceeded smoothly with a low catalyst loading of Bi(OTf)(3)·4H(2)O (0.5-5.0 mol%) to afford the corresponding protected β-amino carbonyl compounds and homoallylic amines in very good yields (up to 96%). The latter compounds could also be obtained via a bismuth-mediated three-component reaction. We have also developed an efficient vinylogous Mukaiyama aldol reaction of 2-(trimethylsilyloxy)furan with various aromatic aldehydes mediated by bismuth triflate in a low catalyst loading (1 mol%). The reaction proceeds rapidly and affords the corresponding 5-[hydroxy(aryl)methyl]furan-2(5H)-ones in high yields with good to very good diastereoselectivities (diastereoisomeric ratios>98:2). Such selectivities, although previously reported with other Lewis acids, could be achieved with a much lower catalyst loading. 5-[Hydroxy(alkyl)methyl]furan-2(5H)-ones derived from ketones could also be obtained with good diastereoselectivities. The vinylogous Mukaiyama aldol reaction has also been extended to 2,2-dimethyl-6-methylene-4-(trimethyl-silyloxy)-1,3-diox-4-ene using 1 mol% of Bi(OTf)(3)·4H(2)O.

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“…This method of addition produced the cis β-lactam 6 as a single stereoisomer in 80% yield [13][14][15][16]. The expected cisconfiguration of 6 was confirmed by 1 H-NMR, which showed a characteristic coupling constant of about 5 Hz for the β-lactam protons [17][18]. Ozonolysis of β-lactam 6 at -78 o C afforded the formyl β-lactam 7 in 90% yield.…”

Section: Resultsmentioning

confidence: 93%

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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Stereochimie en serie β-lactame : Stereochimie de la reaction de reformatzky sur les bases de schiff

Cited by 79 publications

References 9 publications

The synthesis of D,L-cis-N-oxalamido-3-N-phenylacetamido-4-methoxy methyl-2-azetidinone

The synthesis of D,L-cis-N-oxalamido-3-N-phenylacetamido-4-methoxy methyl-2-azetidinone

Bismuth-Catalyzed Addition of Silyl Nucleophiles to Carbonyl Compounds and Imines

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

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