A chemoenzymatic approach to the synthesis of enantiomerically pure aza analogues of paraconic acid methyl ester and both enantiomers of methyl β-proline

Felluga, Fulvia; Pitacco, Giuliana; Prodan, Mario; Pricl, Sabrina; Visintin, Marco; Valentin, Ennio

doi:10.1016/s0957-4166(01)00523-7

Cited by 43 publications

(31 citation statements)

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“…Reduction of acid 6b followed a very similar course to that of 2b and the (S)-(+)-carboxylic acid 5b was isolated in 75% yield and in 97% ee The configuration of 5b was established by comparison with optical rotation data reported for this compound derived by enzymatic resolution 13 and clearly 2b and 6b undergo asymmetric reduction in the same sense as one another under these Rh/WALPHOS conditions. We were interested in the behavior of the isomeric lactam 7 under reduction conditions, recognizing that C=C isomerization could be involved in the reduction of -aminoacrylates such as 6b.…”

Section: Scheme 2 Asymmetric Reduction Of 2b To Give (S)-3bmentioning

confidence: 67%

“…13 This earlier work provided us with a basis of a later structural assignment but two potential reduction substrates needed to be considered: the -aminoacrylates 6a/b 14 (the  4,5 -lactam, analogous to 2a/b) and the corresponding  3,4 -isomer (incorporating a fumarate subunit), previously reported as the methyl ester 7. 15 The synthesis of -aminoacrylate 6a/b we have developed is shown in Scheme 3 and is based on formylation of diethyl succinate followed by enamine formation (using benzylamine), cyclization of which was best carried out under strongly basic conditions.…”

Section: Scheme 2 Asymmetric Reduction Of 2b To Give (S)-3bmentioning

confidence: 99%

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Asymmetric Reduction of Lactam-Based β-Aminoacrylates. Synthesis of Heterocyclic β²-Amino Acids

et al. 2016

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General rightsThis document is made available in accordance with publisher policies. Please cite only the published version using the reference above. ABSTRACT:The ability to affect asymmetric reduction of heterocyclic -aminoacrylates 1 (n=1-3) has been assessed with pyrrolidine and piperidone variants generating the corresponding N-heterocyclic  2 -amino acids 3b and 5b with high enantioselectivity (≥ 97% ee) using a Rh/WALPHOS catalyst combination. The use of the carboxylic acid substrate was essential; the corresponding esters do undergo reduction but led to racemic products. The seven-ring azepanone variant (as the carboxylic acid 9b) underwent reduction but only a minimal level of asymmetric induction was observed.

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Section: Scheme 2 Asymmetric Reduction Of 2b To Give (S)-3bmentioning

confidence: 67%

Section: Scheme 2 Asymmetric Reduction Of 2b To Give (S)-3bmentioning

confidence: 99%

Asymmetric Reduction of Lactam-Based β-Aminoacrylates. Synthesis of Heterocyclic β²-Amino Acids

et al. 2016

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“…The Newton molecular equation of motion was solved by the Verlet leapfrog algorithm [29] with an integration step of 1 fs for a total simulation time of 200 ps. In all cases, the complexation energies E complex were calculated from the equilibrium MD energy components of the non-bonded interactions for the a-CT/lactam complex (E a-CT/ lactam ), the a-CT (E a-CT ), and the lactam (E lactam ) according to [14]:…”

Section: Molecular-mechanics/dynamicsmentioning

confidence: 99%

“…Recently, we described [14] the optical resolution of the methyl esters of 1-alkyl-5-oxopyrrolidine-3-carboxylic acids (7) by chemo-enzymatic hydrolysis of the ester function. Among the commercially available lipases, proteases, and esterases tested [15], a-chymotrypsin (a-CT) turned out to be the choice for resolving most of the lactams studied, since it allows the isolation of the corresponding acids and esters with high enantiomeric excess (ee).…”

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Chemo-Enzymatic Synthesis and Determination of the Absolute Configuration of Both Enantiomers of Methyl trans-5-Oxo-2-pentylpyrrolidine-3-carboxylate Precursors of the Aza Analogues of (+)- and (−)-Methylenolactocin

Felluga¹,

Fermeglia²,

Ferrone³

et al. 2002

HCA

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Dedicated with warm regards to Professor Dieter Seebach on the occasion of his 65th birthday Enantiomerically pure methyl esters of ()-(2R,3S)-and (À)-(2S,3R)-5-oxo-2-pentylpyrrolidine-3-carboxylic acid with 99% and 98% ee were obtained by enzymatic resolution of the corresponding racemic mixture using a-chymotrypsin and pig-liver acetone powder, respectively. Their absolute configurations were established by chemical methods, i.e., conversion of the trans-g-lactam moiety to the corresponding g-lactone of known configuration. The favorable interactions between the trans-g-lactam and a-chymotrypsin were rationalized by molecular-mechanics calculations, which suggest a different situation for the cis-diastereoisomer.

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“…Also, oxidative carbon-carbon cleavage of 3-pipecolinate 11 14 proceeded smoothly to afford 12, which was transformed into enantiomerically pure 4 15,16 (Eq. 8).…”

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Oxidative C–C bond cleavage of N-alkoxycarbonylated cyclic amines by sodium nitrite in trifluoroacetic acid

Onomura

Moriyama

Fukae

et al. 2008

Tetrahedron Letters

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Abstract-Oxidative carbon-carbon bond cleavage of N-alkoxycarbonylated cyclic amines was accomplished by NaNO 2 in TFA to afford ω-amino carboxylic acid in high yield. Optically active 3-hydroxypiperidine derivatives and 3-pipecolinate, were converted to enantiomerically pure (R)-4-amino-3-hydroxybutanoic acid (GABOB) and (S)-2-pyrrolidone-4-carboxylate, respectively.It is well known that trifluoroacetic acid (TFA) acts as an efficient medium for oxidation of hydrocarbons.1 Recently, we found that efficient oxidation of adamantanes to 1-adamantanols was catalyzed by sodium nitrite (NaNO 2 ) under oxygen atmosphere in TFA. 2 In addition, 2 equiv of NaNO 2 in TFA 3 oxidized acyclic and cyclic secondary alcohols to the corresponding ketones and α,ω-dicarboxylic acid, respectively. 4 In the latter case, oxidative cleavage of cyclic secondary alcohols occurred between the α-carbon and the β-carbon. We report herein that this oxidizing agent works well as demonstrated by a unique reaction of N-alkoxycarbonylated cyclic amines 1 which reacted with NaNO 2 to afford the ring-opened products 2 5 and its application to preparation of optically active compounds 3e and 4 (Eq. 1). 2. The oxidation of 1a (1 mmol) was carried out in TFA (5 mL) containing NaNO 2 (2 mmol) and H 2 O (10 mmol) under aerobic condition. The oxidation smoothly proceededKey words: carbon-carbon cleavage; cyclic amines; trifluoroacetic acid; sodium nirite; ω-amino acid * Corresponding author, Tel +81-95-819-2429, Fax +81-95-819-2476 at 0 o C to rt for 3 h to afford an oxidative ring-opened product 2a in 94% yield. The oxidative cleavages of N-protected pyrrolidines 1b-d and piperidines 1e-i with NaNO 2 in TFA were examined to clarify generality of substrates (Eq. 3). The results are summarized in Table 1.

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A chemoenzymatic approach to the synthesis of enantiomerically pure aza analogues of paraconic acid methyl ester and both enantiomers of methyl β-proline

Cited by 43 publications

References 55 publications

Asymmetric Reduction of Lactam-Based β-Aminoacrylates. Synthesis of Heterocyclic β²-Amino Acids

Asymmetric Reduction of Lactam-Based β-Aminoacrylates. Synthesis of Heterocyclic β²-Amino Acids

Chemo-Enzymatic Synthesis and Determination of the Absolute Configuration of Both Enantiomers of Methyl trans-5-Oxo-2-pentylpyrrolidine-3-carboxylate Precursors of the Aza Analogues of (+)- and (−)-Methylenolactocin

Oxidative C–C bond cleavage of N-alkoxycarbonylated cyclic amines by sodium nitrite in trifluoroacetic acid

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A chemoenzymatic approach to the synthesis of enantiomerically pure aza analogues of paraconic acid methyl ester and both enantiomers of methyl β-proline

Cited by 43 publications

References 55 publications

Asymmetric Reduction of Lactam-Based β-Aminoacrylates. Synthesis of Heterocyclic β2-Amino Acids

Asymmetric Reduction of Lactam-Based β-Aminoacrylates. Synthesis of Heterocyclic β2-Amino Acids

Chemo-Enzymatic Synthesis and Determination of the Absolute Configuration of Both Enantiomers of Methyl trans-5-Oxo-2-pentylpyrrolidine-3-carboxylate Precursors of the Aza Analogues of (+)- and (−)-Methylenolactocin

Oxidative C–C bond cleavage of N-alkoxycarbonylated cyclic amines by sodium nitrite in trifluoroacetic acid

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Asymmetric Reduction of Lactam-Based β-Aminoacrylates. Synthesis of Heterocyclic β²-Amino Acids

Asymmetric Reduction of Lactam-Based β-Aminoacrylates. Synthesis of Heterocyclic β²-Amino Acids