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Mosher ester analysis for the determination of absolute configuration of stereogenic (chiral) carbinol carbons


This protocol details the most commonly used nuclear magnetic resonance (NMR)-based method for deducing the configuration of otherwise unknown stereogenic, secondary carbinol (alcohol) centers (R1R2CHOH (or the analogous amines where OH is replaced by NH2)). This 'Mosher ester analysis' relies on the fact that the protons in diastereomeric α-methoxy-α-trifluoromethylphenylacetic acid (MTPA) esters (i.e., those derived from conjugation of the carbinol under interrogation with MTPA) display different arrays of chemical shifts (δs) in their 1H NMR spectra. The protocol consists of the following: (i) preparation of each of the diastereomeric S- and R-MTPA esters and (ii) comparative (ΔδSR) analysis of the 1H NMR spectral data of these two esters. By analyzing the sign of the difference in chemical shifts for a number of analogous pairs of protons (the set of ΔδSR values) in the diastereomeric esters (or amides), the absolute configuration of the original carbinol (or amino) stereocenter can be reliably deduced. A typical Mosher ester analysis requires approximately 4–6 h of active effort over a 1- to 2-d period.

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Figure 1
Figure 2: Commonly encountered representations of the conformations (rotational isomers) used for the analysis of each of the diastereomeric MTPA esters 4S and 4R.
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  1. Stephens, T.D. & Brynner, R. Dark Remedy: The Impact of Thalidomide and Its Revival as a Vital Medicine (Perseus Publishing, Cambridge, MA, 2001).

    Google Scholar 

  2. Seco, J.M., Quiñoá, E. & Riguera, R. The assignment of absolute configuration by NMR. Chem. Rev. 104, 17–117 (2004).

    CAS  Article  Google Scholar 

  3. Dale, J.A. & Mosher, H.S. Nuclear magnetic resonance enantiomer reagents. Configurational correlations via nuclear magnetic resonance chemical shifts of diastereomeric mandelate, O-methylmandelate, and α-methoxy-α-trifluoromethylphenylacetate (MTPA) esters. J. Am. Chem. Soc. 95, 512–519 (1973).

    CAS  Article  Google Scholar 

  4. Hoye, T.R. & Renner, M.K. MTPA (Mosher) amides of cyclic secondary amines: conformational aspects and a useful method for assignment of amine configuration. J. Org. Chem. 61, 2056–2064 (1996).

    CAS  Article  Google Scholar 

  5. Dale, J.A., Dull, D.L. & Mosher, H.S. α-Methoxy-α-trifluoromethylphenylacetic acid, a versatile reagent for the determination of enantiomeric composition of alcohols and amines. J. Org. Chem. 34, 2543–2549 (1969).

    CAS  Article  Google Scholar 

  6. Ward, D.E. & Rhee, C.K. A simple method for the microscale preparation of Mosher's acid chloride. Tetrahedron Lett. 32, 7165–7166 (1991).

    CAS  Article  Google Scholar 

  7. Sullivan, G.R., Dale, J.A. & Mosher, H.S. Correlation of configuration and 19F chemical shifts of α-methoxy-α-trifluoromethylphenylacetate derivatives. J. Org. Chem. 38, 2143–2147 (1973).

    CAS  Article  Google Scholar 

  8. Ohtani, I., Kusumi, T., Ishitsuka, M.O. & Kakisawa, H. Absolute configurations of marine diterpenes possessing a xenicane skeleton. An application of an advanced Mosher's method. Tetrahedron Lett. 30, 3147–3150 (1989).

    CAS  Article  Google Scholar 

  9. Ohtani, I., Kusumi, T., Kashman, Y. & Kakisawa, H. A new aspect of the high-field NMR application of Mosher's method. The absolute configuration of marine triterpene sipholenol A. J. Org. Chem. 56, 1296–1298 (1991).

    CAS  Article  Google Scholar 

  10. Ohtani, I., Kusumi, T., Kashman, Y. & Kakisawa, H. High-field FT NMR application of Mosher's method. The absolute configurations of marine terpenoids. J. Am. Chem. Soc. 113, 4092–4096 (1991).

    CAS  Article  Google Scholar 

  11. Parker, D. NMR determination of enantiomeric purity. Chem. Rev. 91, 1441–1457 (1991).

    CAS  Article  Google Scholar 

  12. Trost, B.M. et al. On the use of the O-methylmandelate ester for establishment of absolute configuration of secondary alcohols. J. Org. Chem. 51, 2370–2374 (1986).

    CAS  Article  Google Scholar 

  13. Moon, S. et al. (+)-7S-Hydroxyxestospongin A from the marine sponge Xestospongia sp. and absolute configuration of (+)-xestospongin D. J. Nat. Prod. 65, 249–254 (2002).

    CAS  Article  PubMed  Google Scholar 

  14. Still, W.C., Kahn, M. & Mitra, A. Rapid chromatographic technique for preparative separations with moderate resolution. J. Org. Chem. 43, 2923–2925 (1978).

    CAS  Article  Google Scholar 

  15. Cahn, R.S., Ingold, C.K. & Prelog, V. The specification of asymmetric configuration in organic chemistry. Experientia 12, 81–94 (1956).

    CAS  Article  Google Scholar 

  16. Joshi, B.S. & Pelletier, S.W. A cautionary note on the use of commercial (R)-MTPA-Cl and (S)-MTPA-Cl in determination of absolute configuration by Mosher ester analysis. Heterocycles 51, 183–184 (1999).

    CAS  Article  Google Scholar 

  17. Garo, E. et al. Trichodermamides A and B, cytotoxic modified dipeptides from the marine-derived fungus Trichoderma virens. J. Nat. Prod. 66, 423–426 (2003).

    CAS  Article  PubMed  Google Scholar 

  18. Hoye, T.R. & Jeffrey, C.S. Student empowerment through 'mini-microscale' reactions: the epoxidation of 1 mg of geraniol. J. Chem. Educ. 83, 919–920 (2006).

    CAS  Article  Google Scholar 

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Hoye, T., Jeffrey, C. & Shao, F. Mosher ester analysis for the determination of absolute configuration of stereogenic (chiral) carbinol carbons. Nat Protoc 2, 2451–2458 (2007).

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