J. McNulty et al. / Tetrahedron Letters 49 (2008) 6344–6347
6347
(0.312 g, 2.00 mmol) in pyridine (3.00 mL) was added diethyl chloro-
phosphate (0.320 mL, 2.10 mmol) slowly at rt in an atmosphere of argon,
and the reaction mixture was stirred at rt for about 30 min. The heterogenous
mixture was heated at 70 °C under argon atmosphere for 3 h, during which the
reaction mixture became homogenous. Pyridine was removed in vacuo, and
the residue partitioned between ethyl acetate (15.0 mL) and saturated sodium
bicarbonate (5.00 mL). After stirring well (10 min), the organic layer was
separated, dried over anhyd Na2SO4 and the solvent evaporated in vacuo to
yield the crude product. In all cases, crude products were >95% pure by 1H
NMR. Purification of 5d over silica gel (5% ethyl acetate in hexane) afforded
0.552 g, 86% yield of pure product 5d.12
References and notes
1. Otera, J. Esterification Methods, Reactions and Applications; Wiley-VCH:
Weinheim, 2003; pp 301–312.
2. (a) Smith, M. B.; March, J. Advanced Organic Chemistry, 5th ed.; Wiley: New
York, 2001; pp 484–490; (b) Larock, C. Comprehensive Organic Transformations,
2nd ed.; Wiley-VCH: New York, 1999; pp 1932–1941.
3. (a) Mitsunobu, O.; Yamada, M. Bull. Chem. Soc. Jpn. 1967, 40, 2380–2382; (b)
Dembinski, R. Eur. J. Org. Chem. 2004, 2763–2772.
4. Inanga, J.; Hirata, K.; Saeki, H.; Katsuki, T.; Yamaguchi, M. Bull. Chem. Soc. Jpn.
1979, 52, 1989–1993.
(b) Typical procedure for the synthesis of L-N-(4-nitro-benzoyl)-Val-OMe 6b:
5. (a) Liu, H. J.; Chan, W. H.; Lee, S. P. Tetrahedron Lett. 1978, 19, 4461–4464; (b)
Adak, A. K. Synlett 2004, 1651–1652.
6. Liu, H. J.; Sabesan, S. I. Can. J. Chem. 1980, 58, 1645–2648.
To a mixture of 4-nitrobenzoic acid (0.334 g, 2.00 mmol) in pyridine (3.00 mL)
was added slowly diethyl chlorophosphate (0.320 mL, 2.10 mmol) at rt in an
atmosphere of argon, and the reaction mixture was stirred at rt for about
7. (a) Kaiho, T.; Masamune, S.; Toyoda, T. J. Org. Chem. 1982, 47, 1612–1614; (b)
Parenty, A.; Moreau, X.; Campagne, J. M. Chem. Rev. 2006, 106, 911–939.
8. (a) McNulty, J.; Nair, J. J.; Cheekoori, S.; Larichev, V.; Capretta, A.; Robertson, A.
J. Chem. Eur. J. 2006, 12, 9314–9322; (b) McNulty, J.; Cheekoori, S.; Nair, J. J.;
Larichev, V.; Capretta, A.; Robertson, A. J. Tetrahedron Lett. 2005, 46, 3641–
3644; (c) Dyck, J.; Zavorine, S.; McNulty, J.; Capretta, A.; Robertson, A. J.;
Larichev, V. J. Organomet. Chem. 2005, 690, 2548–2552; (d) McNulty, J.;
Capretta, A.; Robertson, A. J.; Larichev, V.; Dyck, J. Angew. Chem., Int. Ed. 2003,
42, 4051–4054; (e) McNulty, J.; Capretta, A.; Robertson, A. J.; Larichev, V.; Dyck,
J. J. Org. Chem. 2003, 68, 1597–1600.
45 min. To this was then added L-valine methylester hydrochloride (0.335 g,
2.00 mmol) in one lot, and the reaction mixture was heated to 70 °C under
argon atmosphere for 5 h. After completion of the reaction, pyridine was
removed in vacuo and the residue partitioned between ethyl acetate (15.0 mL)
and saturated sodium bicarbonate solution (5.00 mL) and stirred well for about
10 min. The organic layer was separated, dried over anhyd Na2SO4, and the
solvent was evaporated in vacuo yielding the crude product. Purification of 6b
over silica gel (5% ethyl acetate in hexane) afforded 0.448 g, 80% yield of pure
product 6b.13
12. Cervinka, O.; Kriz, O. Collect. Czech. Chem. Commun. 1973, 38, 938–942.
13. Liley, M. J.; Johnson, T.; Gibson, S. E. J. Org. Chem. 2006, 71, 1322–1329.
9. Won, J. E.; Kim, H. K.; Kim, J. J.; Yim, H. S.; Kim, M. J.; Kang, S. B.; Chung, H. A.;
Lee, S. G.; Yoon, Y. J. Tetrahedron 2007, 63, 12720–12730.
10. Hikota, M.; Tone, H.; Horita, K.; Yonemitsu, O. J. Org. Chem. 1990, 55, 7–9.
11. (a) Typical procedure for the synthesis of
L-menthol-4-chloro cinnamate 5d: To
a
mixture of 4-chlorocinnamic acid (0.365 g, 2.00 mmol) and
L
-menthol