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B. Lygo et al.
LETTER
(9.0 mmol) was added and stirring continued for 4–16 h.
Then, H2O (100 mL) was added and layers separated. The
aqueous was extracted with EtOAc (2 × 100 mL) and the
combined organics were dried (Na2SO4), then concentrated
under reduced pressure. The residue was then purified by
chromatography on silica gel.
E.; Engel, J. C. Tetrahedron 2000, 56, 9747. (f) Goursalin,
B. J.; Lachance, P.; Bonneau, P. R.; Storer, A. C.; Kirschke,
H.; Broemme, D. Bioorg. Chem. 1994, 22, 227.
(g) Giordano, C.; Calabretta, R.; Gallina, C.; Consalvi, V.;
Scandurra, R.; Noya, F. C.; Franchini, C. Eur. J. Med. Chem.
1993, 28, 917. (h) Huang, Z. Y.; McGowan, E. B.; Detwiler,
T. C. J. Med. Chem. 1992, 35, 2048.
Selected NMR Data.
(5) For an alternative approach see: Sarabia, F.; Sanchez-Ruiz,
A.; Chammaa, S. Bioorg. Med. Chem. 2005, 13, 1691.
(6) (a) Lygo, B.; To, D. C. M. Chem. Commun. 2002, 2360.
(b) Lygo, B.; To, D. C. M. Tetrahedron Lett. 2001, 42,
1343. (c) Lygo, B.; Wainwright, P. G. Tetrahedron 1999,
55, 6289. (d) Lygo, B.; Wainwright, P. G. Tetrahedron Lett.
1998, 39, 1599.
(7) For a recent review on epoxidation via asymmetric catalysis,
see: Xia, Q.-H.; Ge, H.-Q.; Ye, C.-P.; Liu, Z.-M.; Su, K.-X.
Chem. Rev. 2005, 105, 1603.
(8) See for example: (a) Jensen, J. S.; Lam, Y.-F.; Helz, G. R.
Environ. Sci. Technol. 1999, 33, 3568. (b) Orton, K. J. P.;
Bradfield, A. E. J. Chem. Soc. 1927, 986.
(9) Lygo, B.; Andrews, B. I. Metal-Catalysed Carbon–Carbon
Bond-Forming Reactions, In Catalysts for Fine Chemical
Synthesis, Vol. 3; Roberts, S. M.; Whittall, J.; Mather, P.;
McCormack, P., Eds.; J. Wiley and Sons, Ltd.: Chichester,
2004, 27–33.
Compound 9a: 1H NMR (400 MHz, CDCl3): d = 7.99–7.95
(2 H, m, ArH), 7.64–7.46 (3 H, m, ArH), 6.60 (1 H, br d, J =
8.5 Hz, NH), 4.72–4.64 (1 H, m, NHCH), 4.27 (1 H, d, J =
2.0 Hz, NHCOCH), 3.78 (3 H, s, OMe), 3.72 (1 H, d, J = 2.0
Hz, ArCOCH), 1.78–1.58 [3 H, m, CH2, CH(CH3)2], 1.01 (3
H, d, J = 6.5 Hz, CH3), 0.99 (3 H, d, J = 6.5 Hz, CH3). 13
C
NMR (100 MHz, CDCl3): d = 191.5 (C), 172.5 (C), 166.2
(C), 134.9 (C), 134.4 (CH), 129.0 (CH), 128.5 (CH), 56.2
(CH), 54.9 (CH), 52.5 (CH3), 50.4 (CH), 41.3 (CH2), 25.0
(CH), 22.7 (CH3), 22.0 (CH3).
Compound 10a: 1H NMR (400 MHz, CDCl3): d = 7.99–7.95
(2 H, m, ArH), 7.64–7.46 (3 H, m, ArH), 6.50 (1 H, br d, J =
8.5 Hz, NH), 4.72–4.64 (1 H, m, NHCH), 4.41 (1 H, d, J =
2.0 Hz, NHCOCH), 3.78 (3 H, s, OMe), 3.73 (1 H, d, J = 2.0
Hz, ArCOCH), 1.78–1.58 [3 H, m, CH2, CH(CH3)2], 1.01 (3
H, d, J = 6.5 Hz, CH3), 0.99 (3 H, d, J = 6.5 Hz, CH3). 13
C
NMR (100 MHz, CDCl3): d = 191.3 (C), 172.9 (C), 166.4
(C), 134.9 (C), 134.4 (CH), 129.0 (CH), 128.5 (CH), 55.8
(CH), 54.9 (CH), 52.5 (CH3), 50.2 (CH), 41.0 (CH2), 24.8
(CH), 22.8 (CH3), 21.7 (CH3).
(10) General Procedure for Asymmetric Epoxidation.
A mixture of 15% aq NaOCl (9.0 mmol) and 12 M aq KOH
(1 mL) was added dropwise to a solution of enone (3.0
mmol) and the appropriate catalyst (0.15 mmol) in PhMe (70
ml). The resulting mixture was stirred vigorously (1000 rpm)
at r.t. for 30 min, then a second portion of 15% aq NaOCl
(11) Tamai, M.; Yokoo, C.; Murata, M.; Oguma, K.; Sota, K.;
Sato, E.; Kanaoka, Y. Chem. Pharm. Bull. 1987, 35, 1098.
(12) For further discussion of this, see: Roush, W. R.; Hernandez,
A. A.; Zepeda, G. Synthesis 1999, 1500.
Synlett 2006, No. 13, 2063–2066 © Thieme Stuttgart · New York