Applications of MTPA (Mosher) amides of secondary amines: Assignment of absolute configuration in chiral cyclic amines

Journal of Organic Chemistry

Volumn 61, Issue 24, 1996, Pages 8489-8495

  Hoye, Thomas R ^a   Renner, Matthew K ^a  

^a University of Minnesota ^*  (United States)

Author keywords

[No Author keywords available]

Indexed keywords

EID: 0000709690     PISSN: 00223263     EISSN: None     Source Type: Journal    
DOI: 10.1021/jo960373b     Document Type: Article

References (28)

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3. (c) Sullivan, G. R.; Dale, J. A.; Mosher, H. S. J. Org. Chem. 1973, 38, 2143.
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8. Hoye, T. R.; Renner, M. K. J. Org. Chem. 1996, 61, 2056.
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11. 2-N-C(=O)-C-C-F].
12. 3,4c
13. For example, see: Fukushi, Y.; Yajima, C.; Mizutani, J. Tetrahedron Lett. 1994, 35, 9417.
14. (a) Munchhof, M. J.; Meyers, A. I. J. Am. Chem. Soc. 1995, 117, 5399.
15. (b) Comins, D. L.; Joseph, S. P.; Goehring, R. R. J. Am. Chem. Soc. 1994, 116, 4719.
16. (c) Comins, D. L.; Benjelloun, N. R. Tetrahedron Lett. 1994, 35, 829.
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18. (e) Rychnovsky, S. D.; McLernon, T. L.; Rajanpakse, H. J. Org. Chem. 1996, 61, 1194.
19. While useful, the modeling techniques described here are nonessential for successful determination of absolute configuration of most chiral secondary amines.
20. Shielding is greater for protons on an axial substituent at C(2) than that for axial protons at C(2).
21. Some protons have been removed for clarity in each of the figures.
22. We refer to individual rotamers as syn or anti on the basis of the relationship of the MTPA α-carbon and the largest ring substituent (e.g., the carbethoxymethyl group in 8 or 9).
23. (a) Lunazzi, L.; Macciantelli, D.; Tassi, D.; Dondoni, A. J. Chem. Soc., Perkin Trans. 2 1980, 717.
24. (b) Chow, Y. L.; Colon, C. J.; Tam, J. N. S. Can. J. Chem. 1968, 46, 2821.
25. 2,2,6,6-Tetramethylpiperidine, for example, could not be derivatized. So far we have been unsuccessful in derivatizing a mixture of cis- and trans-2,6-bis(carbomethoxymethyl)piperidine.
26. 1H NMR spectrum.
27. Baldwin, S. W.; Jeffs, P. W.; Natarajan, S. Synth. Commun. 1977, 7, 79.
28. 1H NMR spectrum of the resulting amide shows two rotamers, present in a ratio of 2.5:1. In the major rotamer, the phenyl is directed toward the C(4) methylene group, while in the minor rotamer it is oriented principally toward the C(6) methylene group.