S. Lühr et al. / Tetrahedron: Asymmetry 24 (2013) 395–401
401
J = 7.0 Hz, CH3); 13C NMR (CDCl3): d = 174.0 (C@O), 61.4 (CH2O),
41.9 (CH2N), 37.1 (CH), 15.1 (CH3), 14.0 (CH3). HRMS (ESI
131.09463) m/z: [M+H]+ calcd for C6H14NO2 132.10191; found:
132.1021, [M+Na]+ calcd. for C6H13NNaO2 154.08385; found:
154.08407.
3. Abele, S.; Seebach, D. Eur. J. Org. Chem. 2000, 1–15.
4. Pseudo-Peptides in Drug Discovery; Nielsen, P. E., Ed.; Wiley-VCH: Weinheim,
2004.
5. Barrow, R. A.; Hemscheidt, T.; Liang, J.; Paik, S.; Moore, R. E.; Tius, M. A. J. Am.
Chem. Soc. 1995, 117, 2479–2490.
6. Ding, Y.; Rath, C. M.; Bolduc, K. L.; Håkansson, K.; Sherman, D. H. J. Am. Chem.
Soc. 2011, 133, 14492–14495.
7. Nazaré, M.; Waldmann, H. Angew. Chem., Int. Ed. 2000, 39, 1125–1128.
8. Nazaré, M.; Waldmann, H. Chem. Eur. J. 2001, 7, 3363–3376.
9. Juaristi, E.; Quintana, D.; Balderas, M.; García-Pérez, E. Tetrahedron: Asymmetry
1996, 7, 2233–2246.
4.13. Synthesis of (S)-3-amino-2-methyl-propan-1-ol
trifluoroacetate 8
10. Agami, C.; Cheramy, S.; Dechoux, L.; Melaimi, M. Tetrahedron 2001, 57, 195–
200.
11. Gutiérrez-García, V. M.; Reyes-Rangel, G.; Muñoz-Muñiz, O.; Juaristi, E. Helv.
Chim. Acta 2002, 85, 4189–4199.
12. Beddow, J. E.; Davies, S. G.; Ling, K. B.; Roberts, P. M.; Russell, A. J.; Smith, A. D.;
Thomson, J. E. Org. Biomol. Chem. 2007, 5, 2812–2825.
13. Shustov, G. V.; Rauk, A. Tetrahedron: Asymmetry 1996, 7, 669–708.
14. Zhu, G.; Chen, Z.; Zhang, X. J. Org. Chem. 1999, 64, 6907–6910.
15. Heller, D.; Holz, J.; Drexler, H.-J.; Lang, J.; Drauz, K.; Krimmer, H.-P.; Börner, A. J.
Org. Chem. 2001, 66, 6816–6817.
16. Holz, J.; Monsees, A.; Jiao, H.; You, J.; Komarov, I. V.; Fischer, C.; Drauz, K.;
Börner, A. J. Org. Chem. 2003, 68, 1701–1710.
17. Reetz, M. T.; Li, X. Angew. Chem., Int. Ed. 2005, 44, 2959–2962.
18. Holz, J.; Zayas, O.; Jiao, H.; Baumann, W.; Spannenberg, A.; Monsees, A.;
Riermeier, T. H.; Almena, J.; Kadyrov, R.; Börner, A. Chem. Eur. J. 2006, 12, 5001–
5013.
19. Landert, H.; Spindler, F.; Wyss, A.; Blaser, H.-U.; Pugin, B.; Ribourduoille, Y.;
Gschwend, B.; Ramalingam, B.; Pfaltz, A. Angew. Chem., Int. Ed. 2010, 49, 6873–
6876.
20. Wu, Y.; Qi, S.-B.; Wu, F.-F.; Zhang, X.-C.; Li, M.; Wu, J.; Chan, A. S. C. Org. Lett.
2011, 13, 1754–1757.
To a solution of 6b (1 mmol, 189 mg) in dichloromethane (5 mL)
was added trifluoroacetic acid (1.5 mL). The solution was stirred at
room temperature for 3 h, after which the volatile material was
evaporated with a rotavapor. The syrup product corresponds to
the TFA salt 8. ½a D23
ꢁ
¼ ꢀ8:2 (c 1.0, MeOH). 1H NMR (CD3OD):
d = 3.64 (1H, dd, J = 10.8, 4.6 Hz, Ha-CH2O), 3.64 (1H, dd, J = 10.8,
7.8 Hz, Hb-CH2O), 3.00 (1H, dd, J = 12.7, 7.6 Hz, Ha-CH2N), 2.85
(1H, dd, J = 12.7, 6.0 Hz, Hb-CH2N), 2.00 (1H, m, CH), 0.97 (3H, d,
J = 6.9 Hz, CH3); 13C NMR (CD3OD): d = 162.9 (q, J = 38 Hz, C@O),
118.2 (q, J = 287 Hz, CF3), 66.6 (CH2O), 45.0 (CH2N), 35.0 (CH),
14.4 (CH3); 19F NMR (CD3OD) d = ꢀ76.5. HRMS (ESI 90.09189) m/
z: [M⁄]+ calcd for C4H12NO+ 90.09134; found: 90.09184. Anal. calcd
for C6H12F3NO3 (203.160): C, 35.47; H, 5.95; F, 28.05; N, 6.89.
Found: C, 35.75; H, 5.60; F, 27.87; N, 6.66.
4.14. Synthesis of (S)-3-(tert-butoxycarbonylamino)-2-methyl-
propyl acetate 9
21. Pignataro, L.; Boghi, M.; Civera, M.; Carboni, S.; Piarulli, U.; Gennari, C. Chem.
Eur. J. 2012, 18, 1383–1400.
22. Imamoto, T.; Tamura, K.; Zhang, Z.; Horiuchi, Y.; Sugiya, M.; Yoshida, K.;
Yanagisawa, A.; Gridnev, I. D. J. Am. Chem. Soc. 2012, 134, 1754–1769.
23. Eilitz, U.; Lessmann, F.; Seidelmann, O.; Wendisch, V. Tetrahedron: Asymmetry
2003, 14, 189–192.
24. Lühr, S.; Holz, J.; Zayas, O.; Wendisch, V.; Börner, A. Tetrahedron: Asymmetry
2012, 23, 1301–1319.
25. Saylik, D.; Campi, E. M.; Donohue, A. C.; Jackson, W. R.; Robinson, A. J.
Tetrahedron: Asymmetry 2001, 12, 657–667.
26. Huang, H.; Liu, X.; Deng, J.; Qiu, M.; Zheng, Z. Org. Lett. 2006, 8, 3359–3362.
27. Wieland, J.; Breit, B. Nat. Chem. 2010, 2, 832–837.
The racemic mixture of alcohol 6b (75 mg, 0.4 mmol) was dis-
solved in 2 ml of dichloromethane at 0 °C. To the solution triethyl-
amine (60 mg, 0.6 mmol) and acetyl chloride (40 mg, 5 mmol)
were added. After stirring for 1 h at 0 °C and for a further 2 h at
ambient temperature the mixture was evaporated and the residue
was purified by chromatography (cyclohexane/AcOEt = 4:1) to
yield 9 (40 mg, 46%). 1H NMR (CDCl3) d = 4.75 (1H, br s, NH), 3.98
(2H, dd, J = 11.2, 5.4 Hz, Ha-CH2O), 3.92 (2H, dd, J = 11.2, 6.2 Hz,
Hb-CH2O), 3.04 (2H, br d, J = 6.5 Hz, CH2N), 2.03 (3H, s, CH3), 1.95
(1H, m, CH), 1.40 (9H, s, (CH3)3), 0.91 (3H, d, J = 6.9 Hz, CH3); 13C
NMR (CDCl3): d = 171.2 (C@O), 156.0 (C@O), 79.2 (O-C), 66.7
(CH2O), 43.3 (CH2N), 33.4 (CH), 28.3 (CH3), 20.8 (CH3), 14.6 (CH3).
HRMS (ESI 231.14706) m/z: [M+Na]+ calcd for C11H21NNaO4
254.13628; found: 254.13605. The racemate of 9 could be sepa-
rated by gas chromatography (25 m, Lipodex E). For the determina-
tion of the enantiomeric excess of 6b, to a solution of the residue in
DCM were added 1.5 equiv of Et3N and 1.2 equiv of acetyl chloride;
thus the enantiomeric purity of the in situ formed N-Boc-derivative
9 could be analyzed.
ˇ ˇ
28. Zupancic, B.; Mohar, B.; Stephan, M. Org. Lett. 2010, 12, 1296–1299.
29. Deng, J.; Hu, X.-P.; Huang, J.-D.; Yu, S.-B.; Wang, D.-Y.; Duan, Z.-C.; Zheng, Z. J.
Org. Chem. 2008, 73, 2015–2017.
30. Guo, Y.; Shao, G.; Li, L.; Wu, W.; Li, R.; Li, J.; Dong, J.; Qiu, L.; Prashad, M.;
Kwong, F. Y. Adv. Synth. Catal. 2010, 352, 1539–1553.
ˇ ˇ
31. Zupancic, B.; Mohar, B.; Stephan, M. Org. Lett. 2010, 12, 3022–3025.
32. Elaridi, J.; Thaqi, A.; Prosser, A.; Jackson, W. R.; Robinson, A. J. Tetrahedron:
Asymmetry 2005, 16, 1309–1316.
33. Yu, C.; Liu, B.; Hu, L. J. Org. Chem. 2001, 66, 5413–5418.
34. Aranha, R. M.; Bowser, A. M.; Madalengoitia, J. S. Org. Lett. 2009, 11, 575–578.
35. Hoen, R.; Tiemersma-Wegman, T.; Procuranti, B.; Lefort, L.; de Vries, J. G.;
Minnaard, A. J.; Feringa, B. L. Org. Biomol. Chem. 2007, 5, 267–275.
36. Basavaiah, D.; Satyanarayana, T. Chem. Commun. 2004, 32–33.
37. Kippo, T.; Fukuyama, T.; Ryu, I. Org. Lett. 2011, 13, 3864–3867.
38. Tong, X.; Lai, J.; Guo, B.-H.; Huang, Y. J. Polym. Sci., Part A: Polym. Chem. 2011, 49,
1513–1516.
39. Huck, J.; Receveur, J.-M.; Roumestant, M.-L.; Martinez, J. Synlett 2001, 1467–
1469.
Acknowledgements
40. Huck, J.; Duru, C.; Roumestant, M. L.; Martinez, J. Synthesis 2003, 2165–2166.
41. catASiumÒMQF(R) is the name for the chiral bisphospholane ligand
(2R,20R,5R,50R)-1,10-(perfluoro-cyclobut-1-ene-1,2-diyl)bis(2,5-
dimethylphospholane) out of a large family of related bisphospholane ligands
(for more information see Ref. 18).
42. Such migration was already described by Yamamoto with the related N-
methoxycarbonyl-substrate: Takagi, M.; Yamamoto, K. Tetrahedron 1991, 47,
8869–8882.
43. For the (R)-enantiomer of 4d, a negative sign for the rotation was published:
Gosh, A. K.; Bischoff, A. Eur. J. Org. Chem. 2004, 2131–2141.
44. For the (R)-enantiomer of 4e, a negative sign for the rotation was published:
Solymár, M.; Liljeblad, A.; Lázár, L.; Fülöp, F.; Kanerva, L. T. Tetrahedron:
Asymmetry 2002, 13, 1923–1928.
We acknowledge the highly skilled technical assistance by Mrs.
G. Wenzel and Mrs. H. Borgwaldt. For the analytics of the hydroge-
nation products by HPLC and GC, we thank Dr. C. Fischer, Mrs. S.
Schareina and Mrs. S. Buchholz. We appreciate the financial sup-
port by AiF GmbH. We thank Dr. R. Kadyrov for helpful advice
and Evonik Industries GmbH for the generous gift of phosphorus li-
gands and precatalysts.
References
45. Brown, P.; Southgate, R. Tetrahedron Lett. 1986, 27, 247–250.
46. Holz, J.; Schäffner, B.; Zayas, O.; Spannenberg, A.; Börner, A. Adv. Synth. Catal.
2008, 350, 2533–2545.
47. Pautigny, C.; Jeulin, S.; Ayad, T.; Zhang, Z.; Genêt, J.-P.; Ratovelomanana-Vidal,
V. Adv. Synth. Catal. 2008, 350, 2525–2532.
1. Enantioselective Synthesis of b-Amino Acids; Juaristi, E., Soloshonok, V. A., Eds.,
2nd ed.; Wiley-VCH: Weinheim, 2005.
2. Porter, E. A.; Wang, X.; Lee, H.-S.; Weisblum, B.; Gellman, S. H. Nature 2000, 404,
565.