Regiospecific and Enantiospecific Ring Opening of Methyl (+)-(1'R, 2R)- and (-)-(1'R, 2S)-1-(2-phenylethanol) Aziridine-2-carboxylates
Abstract
:Introduction
Results and Discussion
Conclusions
Experimental
General
Preparation of α-chloro-β-aminoester (3) or (4) hydrochloride
Spectral Data
Acknowledgements
References and Notes
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- Using the general procedure [9] for obtaining of (1) and (2), we prepared the methyl (+)-(1'S, 2R)-1-(2-phenylethanol)aziridine-2-carboxylate and methyl (+)-(1'S, 2S)-1-(2-phenylethanol) aziridine-2-carboxylate from (S)-(+)-2-phenylglycinol. The acid-catalyzed ring opening of methyl (+)-(1'S, 2R)-1-(2-phenylethanol) aziridine-2-carboxylate lead quantitatively to the enantiopure (+)-(1'S, 2S) α-chloro-β-aminoester hydrochloride: m.p.=105-107°C. [α]D = + 30.0 (c=10, CH2Cl2). The (+)-(1'S, 2S)-1-(2-phenylethanol) aziridine-2-carboxylates afforded quantitatively to the enantiopure (+)-(1'S, 2R) α-chloro-β-aminoester hydrochloride: m.p. =111-113°C. [α]D = +57.9 (c=10, CH2Cl2). The magnitude of [α]D and m.p. found for these products are comparable with the corresponding enantiomers (4HCl) and (3HCl) respectively and the NMR spectral data are identical.
- Aziridine (1) (1´R, 2R): yield 70%; m.p. =58-60°C. [α]D = +36.96 (c = 26, CH2Cl2); IR (KBr): 3600-3300, 2953, 1740, 1201 cm-1. NMR 1H: δ (ppm, CDCl3 , JHz): 7.30-7.35 (5H, m, aromatic); 3.93 (1H-4, dd, 11.32, 6.96); 3.83 (1H-4´, dd, 11.32, 4.76); 3.70 (3H, s); 2.74 (1H-1´, dd, 6.9, 4.8); 2.44 (1H-3´, dd, 3.0, 1.1); 2.06 (1H-3, dd, 6.5, 1.1); OH, 2.07 Br s; 2.08 (1H-2, dd, 6.5, 3.0). NMR 13C: δ (ppm, CDCl3): C-i, 139.04; 2C-o, 127.35; 2C-m, 127.90; C-p, 128.63; C-2, 36.42; C-3, 34.69; C-1', 75.20; C-4, 67.74; C-6, 52.31; C-5, 171.23. Aziridine (2) (1´R, 2S): yield 30%; m.p. =105-106°C; [α]D = -126.20 (c = 10, CH2Cl2). IR (KBr): 3500-3400, 2930, 1730, 1245 cm.-1. NMR 1H: δ (ppm, CDCl3 , J Hz): 7.31-740 (5H, m, aromatic); 3.92 (H-4, dd, 11.40, 6.80); 3.80 (H-4´, dd, 11.40, 4.80); 3.78 (3H, s); 2.75 (1H-1´, dd, 6.8, 4.2); 2.49 (H-2, dd, 6.5, 3.2); 2.14 (H-3, d, 3.2); OH, 2.28 Broad singlet; 1.58 (1H-3´, d, 6.5). 13C NMR: δ (ppm, CDCl3): Ci, 138.99; 2C-o, 127.73; 2Cm, 128.50; C-p, 127.90; C-2, 39.21; C-3, 31.49; C-1', 74.91; C-4, 67.52; C-6, 52.44; C-5, 171.07.
- When (3HCl) or (4HCl) was refluxed in Et3N/Acetone, we obtained quantitatively the corresponding enantiopure aziridines (1) and (2) respectively. These results can be explained by an SN2 mechanism.
- Galindo, A.; Orea, L.; Gnecco, D.; Enríquez, R.G.; Toscano, R.A.; Reynolds, W.F. Tetrahedron: Asymmetry 1997, 8, 17, 2877–2879.
- Sample Availability: Available from the authors.
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Gnecco, D.; Orea, L.F.; Galindo, A.; Enríquez, R.G.; Toscano, R.A.; Reynolds, W.F. Regiospecific and Enantiospecific Ring Opening of Methyl (+)-(1'R, 2R)- and (-)-(1'R, 2S)-1-(2-phenylethanol) Aziridine-2-carboxylates. Molecules 2000, 5, 998-1003. https://doi.org/10.3390/50800998
Gnecco D, Orea LF, Galindo A, Enríquez RG, Toscano RA, Reynolds WF. Regiospecific and Enantiospecific Ring Opening of Methyl (+)-(1'R, 2R)- and (-)-(1'R, 2S)-1-(2-phenylethanol) Aziridine-2-carboxylates. Molecules. 2000; 5(8):998-1003. https://doi.org/10.3390/50800998
Chicago/Turabian StyleGnecco, Dino, Laura F. Orea, Alberto Galindo, Raúl G. Enríquez, R. A. Toscano, and W. F. Reynolds. 2000. "Regiospecific and Enantiospecific Ring Opening of Methyl (+)-(1'R, 2R)- and (-)-(1'R, 2S)-1-(2-phenylethanol) Aziridine-2-carboxylates" Molecules 5, no. 8: 998-1003. https://doi.org/10.3390/50800998