Absolute configuration of 1,n-diols by NMR: The importance of the combined anisotropic effects in bis-arylmethoxyacetates

Organic Letters

Volumn 2, Issue 21, 2000, Pages 3261-3264

  Seco, José Manuel ^a   Martino, Marco ^a   Quiñoá, Emilio ^a   Riguera, Ricardo ^a  

^a Santiago de Compostela Spain   (Spain)

Author keywords

[No Author keywords available]

Indexed keywords

EID: 0000810155     PISSN: 15237060     EISSN: None     Source Type: Journal    
DOI: 10.1021/ol0062852     Document Type: Article

References (25)

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2. (b) Trost, B. M.; Belletire, J. L.; Goldleski, P. G.; McDougal, P. G.; Balkovec, J. M.; Baldwin, J. J.; Christy, M. E.; Ponticello, G. S.; Varga, S. L.; Springer, J. P. J. Org. Chem. 1986, 51, 2370-2374.
3. (c) Ohtani, I.; Kusumi, T.; Kashman, Y.; Kakisawa, H. J. Am. Chem. Soc. 1991, 113, 4092-4096.
4. (d) Seco, J. M.; Latypov, Sh. K.; Quiñoá E.; Riguera R. Tetrahedron Lett. 1994. 35, 2921-2924.
5. (e) Seco, J. M.; Latypov, Sh. K.; Quiñoá, E.; Riguera, R. Tetrahedron 1997, 53, 8541-8567.
6. (f) Seco, J. M.; Latypov, Sh. K.; Quiñoá E.; Riguera R. J. Org. Chem. 1997, 62, 7569-7574.
7. (g) Latypov, Sh. K.; Seco, J. M.; Quiñoá, E.; Riguera, R. J. Am. Chem. Soc. 1998, 120, 877-882.
8. (h) Latypov, Sh. K.; Ferreiro, M. J.; Quiñoá, E.; Riguera, R. J. Am. Chem. Soc. 1998, 120, 4741-4751.
9. (i) Ferreiro, M. J.; Latypov, Sh. K.; Quiñoá, E.; Riguera, R. J. Org. Chem. 2000, 65, 2658-2666.
10. (j) López, B.; Quiñoá, E.; Riguera, R. J. Am. Chem. Soc. 1999, 121, 9724-9725.
11. (k) Seco, J. M.; Quiñoá, E.; Riguera, R. Tetrahedron 1999, 55, 569-584.
12. (l) Seco, J. M.; Quiñoá, E.; Riguera, R. J. Org. Chem. 1999, 64, 4669-4675.
13. (a) Seco, J. M.; Quiñoá, E.; Riguera, R. Tetrahedron: Asymmetry 2000, 11, 2781-2791 and references therein.
14. (b) The conformational composition of MTPA esters is more complex than that of AMAAs (MPA, 9-AMA), which makes that reagent less recommended. See refs 2a and 4b.
15. RS is usually employed.
16. (a) Latypov, Sh. K.; Seco, J. M.; Quiñoá E.; Riguera R. J. Org. Chem. 1995, 60, 504-515.
17. (b) Latypov, Sh. K.; Seco, J. M.; Quiñoá E.; Riguera R. J. Org. Chem. 1996, 61, 8569-8577.
18. See Figure 1S in Supporting Information.
19. This is in contrast with the case of isolated secondary alcohols, where the chemical shifts of CαH have no diagnostic value.
20. Shielding originates from the aryl ring of one AMAA unit in one diester and from the aryl ring of the other AMAA unit in the other diester as shown in Figure 1c,d.
21. The quantitative result of the combination of shielding effects clearly depends on the distances involved and the strength of the auxiliary reagent used. For instance, 9-AMA and 2-NMA project their shielding cone further and with more intensity than MPA.
22. 2 > H. This point must be taken into account when the substituents have other priorities. However, the drawings always represent the real situation and can be used as such.
23. Duret, P.; Waechter, A.; Figadere, B.; Hocquemiller, R.; Cavé, A. J. Org. Chem. 1998, 63, 4717-4720.
24. 2 and, as predicted (see Figure 2), those values are useless for assignment purposes.
25. SR data obtained for compound 13 illustrates the application of this method to MTPA diesters. For experimental details on compound 13, see: Woo, M. H.; Cho, K. Y.; Zhang, Y.; Zeng, L.; Gu, Z.-M.; McLaughlin, J. L. J. Nat. Prod. 1995, 58, 1533-1542.