Synthesis of type II β-turn surrogate dipeptides based on syn-α-amino-α,β-dialkyl-β-lactams

Organic Letters

Volumn 6, Issue 24, 2004, Pages 4443-4446

  Palomo, Claudio ^a   Aizpurua, Jesus M ^a   Ganboa, Iñaki ^a   Benito, Ana ^a   Cuerdo, Lourdes ^a   Fratila, Raluca M ^a   Jimenez, Azucena ^a   Loinaz, Iraida ^a   Miranda, José I ^a   Pytlewska, Kinga R ^a   Micle, Andreea ^a   Linden, Anthony ^b  

^a UNIVERSITY OF THE BASQUE COUNTRY UPV EHU   (Spain)

^b UNIVERSITY OF ZURICH   (Switzerland)

Author keywords

[No Author keywords available]

Indexed keywords

BETA LACTAM DERIVATIVE; DIPEPTIDE DERIVATIVE; METHYL GROUP; TRIMETHYLSILYL DERIVATIVE;

ALKYLATION; ARTICLE; BIOMIMETICS; BIOTRANSFORMATION; CHIRALITY; DERIVATIZATION; METHYLATION; PEPTIDE SYNTHESIS; REACTION ANALYSIS; STEREOCHEMISTRY;

ALKYLATION; BETA-LACTAMS; DIPEPTIDES; PROTEIN STRUCTURE, SECONDARY; STEREOISOMERISM;

EID: 10044262066     PISSN: 15237060     EISSN: None     Source Type: Journal    
DOI: 10.1021/ol048348c     Document Type: Article

References (14)

1. Kahn, M.; Eguchi, M. Synthesis of Peptides Incorporating β-Turn Inducers and Mimetics. In Houben-Weyl, Methods of Organic Chemistry; Felix, A., Moroder, L., Toniolo, C., Eds.; Thieme: Stuttgart, 2003; Vol. E22c, pp 695-740 and references therein.
2. Palomo, C.; Aizpurua, J. M.; Benito, A.; Miranda, J. I.; Fratila, R. M.; Matute, C.; Domercq, M.; Gago, F.; Martin-Santamaria, S.; Linden, A. J. Am. Chem. Soc. 2003, 125, 16243-16260.
3. (a) Palomo, C.; Aizpurua, J. M.; Galarza, R.; Benito, A.; Khamrai, U.K.; Eikeseth, U.; Linden, A. Tetrahedron 2000, 56, 5563-5570.
4. (b) Palomo, C.; Aizpurua, J. M.; Benito, A.; Galarza, R.; Khamrai, U.K.; Vazquez, J.; DePascual-Teresa, B.; Nieto, P. M.; Linden, A. Angew. Chem., Int. Ed. 1999, 38, 3056-3058.
5. (a) Ojima, I.; Chen, H.-J. C.; Qiu, X. Tetrahedron 1988, 44, 5307-5318.
6. (b) Ojima, I. Acc. Chem. Res. 1995, 28, 383-389.
7. (c) Ojima, I. In The Organic Chemistry of β-Lactams; Georg, G. I., Ed.; VCH: New York, 1992; p 197.
8. (d) Högberg, H.-E., Jr. In Houben-Weyl, Stereoselective Synthesis; Helmchen, G., Hoffmann, R. W., Mulzer, J.; Schaumann, E.; Thieme: Stuttgart, 1996; E21 Vol. 2, p 791.
9. In contrast to conventional imines that only afford β-aryl-β- lactams upon Staudinger [2 + 2] cycloaddition with aminoketenes, imines 9 give either β-aryl-, β-alkyl-, or β-unsubstituted β-lactams in good yields and excellent stereoselectivities; see: (a) Palomo, C.; Aizpurua, J. M.; Legido, M.; Galarza, R.; Deya, P. M.; Dunogues, J.; Picard, J. P.; Ricci, A.; Seconi, G. Angew. Chem., Int. Ed. Engl. 1996, 35, 1239-1241. (b) Palomo, C.; Aizpurua, J. M.; Legido, M.; Mielgo, A.; Galarza, R. Chem. Eur. J. 1997, 3, 1432-1441.
10. In contrast to conventional imines that only afford β-aryl-β- lactams upon Staudinger [2 + 2] cycloaddition with aminoketenes, imines 9 give either β-aryl-, β-alkyl-, or β-unsubstituted β-lactams in good yields and excellent stereoselectivities; see: (a) Palomo, C.; Aizpurua, J. M.; Legido, M.; Galarza, R.; Deya, P. M.; Dunogues, J.; Picard, J. P.; Ricci, A.; Seconi, G. Angew. Chem., Int. Ed. Engl. 1996, 35, 1239-1241. (b) Palomo, C.; Aizpurua, J. M.; Legido, M.; Mielgo, A.; Galarza, R. Chem. Eur. J. 1997, 3, 1432-1441.
11. Although partial isomerization and decomposition was detected in some instances for the lithium enolates of α-diphenyloxazolidinyl-β- lactams (14-16; R = Ph), this problem was solved by warming immediately the mixtures of the enolates and alkyl halides from -78 to -30°C. See Supporting Information for details.
12. MacSpartan Plus, version 1.2.2; Wavefunction, Inc: Irvine, CA. The actual origin of the discrimination between the syn and anti alkylation paths is given by the energy differences of the respective transition states and not necessarily by the relative stability of the enolate intermediates.
13. For crystallographic evidence concerning the tetrahedral character of the nitrogen atom in lactams and amides, see: (a) Laube, T.; Dunitz, J. D.; Seebach, D. Helv. Chim. Acta 1985, 68, 1373-1393. (b) Laube, T.; Seebach, D. Chem. Ber. 1985, 118, 764-773.
14. For crystallographic evidence concerning the tetrahedral character of the nitrogen atom in lactams and amides, see: (a) Laube, T.; Dunitz, J. D.; Seebach, D. Helv. Chim. Acta 1985, 68, 1373-1393. (b) Laube, T.; Seebach, D. Chem. Ber. 1985, 118, 764-773.