- Enantiopure synthesis of all four stereoisomers of carbapenam-3-carboxylic acid methyl ester
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The retro-Dieckmann reaction has been used as a stereodivergent synthetic tool on N-Boc-7-azabicyclo[2.2.1]heptan-2-one-1-carboxylic acid methyl ester to obtain enantiopure trans- and cis-5-(carboxymethyl)pyrrolidine-2-carboxylic acid methyl esters. These disubstituted pyrrolidines have been used as starting materials to develop concise and straightforward syntheses of all four stereoisomers of carbapenam-3-carboxylic acid methyl esters. In this way, we have confirmed unequivocally the stereochemistry of two carbapenams isolated from strains of Serratia and Erwinia species.
- Avenoza, Alberto,Barriobero, Jose I.,Busto, Jesus H.,Peregrina, Jesus M.
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p. 2889 - 2894
(2007/10/03)
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- Convenient syntheses of (3S,5S)-carbapenam-3-carboxylates and their biosynthetic relevance
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Starting from readily available glutamate derivatives, facile stereoselective syntheses of (3S,5S)-carbapenam-3-carboxylates have been developed. Their significance in confirming the absolute configuration of the natural material is discussed.
- Bycroft, Barrie W.,Chhabra, Siri Ram,Kellam, Barrie,Smith, Paul
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p. 973 - 976
(2007/10/03)
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- Diastereoselective synthesis of 3,5-trans-(+)-(3R,5R)-3-carbomethoxycarbapenam from 3-hydroxypyridine: Questioning the stereochemical assignment of the natural product
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An enantio- and diastereoselective synthesis of the methyl ester of 3,5-trans-(3R,5R)-carbapenam-3-carboxylic acid from 3-hydroxypyridine via (2R,5S)-trans-5-acetoxy-2-allylpiperidine has been achieved by employing the piperidine-pyrrolidine ring-contract
- Tanaka, Hideyuki,Sakagami, Hideki,Ogasawara, Kunio
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- Azabicyclo[3.2.0]heptan-7-ones (carbapenams) from pyrrole
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The azabicyclo[3.2.0]heptan-7-ones 4, 10, 16 and 24 have been prepared from pyrrole. The same general approach has been used for all these derivatives; namely, substitution of pyrrole at the 2- and 5-carbon atoms, catalytic hydrogenation to produce pyrrolidine-2-acetic acid derivatives, and cyclisation using tris(1,3-dihydro-2-oxobenzoxazol-3-yl)phosphine oxide 6. The catalytic hydrogenation of 2,5-disubstituted pyrroles gives only the corresponding cis-2,5-disubstituted pyrrolidines. The hydrogenation proceeds more easily when the nitrogen atom bears a tert-butoxycarbonyl substituent. The N-tert-butoxycarbonylpyrroles 8 and 21 bearing an α-substituent in the acetate side chain were hydrogenated with a high degree of facial stereoselectivity. This allowed the 6-phthalimidoazabicyclo-[3.2.0]heptan-7-one 24 to be isolated as a single diastereoisomer. The X-ray crystal structure of a precursor, the triester, 22a, has been obtained.
- Gilchrist, Thomas L.,Lemos, Americo,Ottaway, Carol J.
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p. 3005 - 3012
(2007/10/03)
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- SYNTHESIS OF 3,5-TRANS-3-METHOXYCARBONYL-1-CARBAPENAM FROM METHYL (+/-)-PYROGLUTAMATE
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Synthesis of 3,5-trans-3-methoxycarbonyl-1-carbapenam in six steps from methyl (+/-)-pyroglutamate is described.
- Nagasaka, Tatsuo,Tsukada, Atsuhiko,Hamaguchi, Fumiko
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p. 2015 - 2022
(2007/10/02)
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