Helvetica Chimica Acta – Vol. 94 (2011)
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The combined org. layer was washed with sat. NaHCO3, soln. and brine, dried (Na2SO4), and
concentrated and the residue purified by CC (AcOEt/hexane 8 :92): 9 (1.23 g, 84%). Colorless liquid.
[a]2D5 ¼ þ30.8 (c ¼ 2.35, CHCl3). IR (neat): 2955, 2880, 1732, 1635, 1460, 1406, 1259, 1184, 1063. 1H-NMR
(300 MHz, CDCl3): 6.47 – 6.41 (m, 1 H); 6.19 – 6.07 (m, 2 H); 5.87 – 5.69 (m, 2 H); 5.31 – 5.25 (m, 1 H);
5.18 – 5.13 (m, 2 H); 4.37 – 4.28 (m, 1 H); 3.99 – 3.82 (m, 2 H); 1.32 (s, 6 H) 0.94 (t, J ¼ 7.93, 9 H); 0.59 (q,
J ¼ 7.5, 6 H). 13C-NMR (100 MHz, CDCl3): 165.28; 136.89; 131.67; 128.15; 116.52; 108.46; 75.44; 73.95;
72.32; 65.47; 26.31; 25.26; 6.69 (3 C); 4.73 (3 C). ESI-MS: 379 ([M þ Na]þ).
(1S,2R)-1-[(1R)-1,2-Dihydroxyethyl]-2-hydroxybut-3-en-1-yl Prop-2-enoate (¼1,2-Dideoxy-d-ara-
bino-hex-1-enitol 4-(Prop-2-enoate); 10). To a soln. of 9 (1.2 g, 3.37 mmol) in MeOH (20 ml) was added
Dowex-50 (Hþ) resin (100 mg), and the mixture was stirred for 6 h at r.t. After completion of the reaction
(TLC monitoring), the mixture was filtered, the filtrate concentrated, and the residue purified by CC
(AcOEt/hexane 7:3): 10 (0.64 g, 94%). Viscous liquid. [a]2D5 ¼ þ9.7 (c ¼ 0.65, CHCl3). IR (neat): 3448,
1
2956, 2884, 1735, 1630, 1461. H-NMR (500 MHz, CDCl3): 6.51 (d, J ¼ 17.3, 1 H); 6.23 – 6.09 (m, 1 H);
6.06 – 5.87 (m, 2 H); 5.41 (d, J ¼ 17.1, 1 H); 5.29 (d, J ¼ 10.5, 1 H); 4.48 – 4.35 (m, 3 H); 4.02 – 3.97 (m,
1 H); 3.56 – 3.54 (m, 1 H); 3.32 – 3.06 (br. s, 1 H); 3.02 – 2.77 (br. s, 1 H); 2.03 – 1.75 (br. s, 1 H). 13C-NMR
(CDCl3, 75 MHz): 166.9; 137.2; 131.9; 127.7; 117.1; 73.0; 71.8; 70.7; 66.1. ESI-MS: 225 ([M þ Na]þ).
(1S,2R)-2-(Acetyloxy)-1-[(1R)-1-(acetyloxy)-2-(benzyloxy)ethyl]but-3-en-1-yl Prop-2-enoate
(¼1,2-Dideoxy-d-arabino-hex-1-enitol 3,5-Diacetetate 6-Benzoate A-(Prop-2-enoate) 11). To a cooled
(08) soln. of 10 (0.6 g, 2.9 mmol) in CH2Cl2 (15 ml) was added pyridine (1.43 ml, 17.4 mmol) followed by
BzCl (0.36 ml, 3.04 mmol), and the mixture stirred at 08 for 3 h. Then Ac2O (0.65 ml, 7 mmol) was added
and stirred at r.t. for additional 4 h. After completion of the reaction, the mixture was diluted with H2O
(10 ml) and extracted with CH2Cl2 (3 ꢁ 15 ml). The combined org. layer was washed with sat. NaHCO3
soln., H2O, and brine, dried (Na2SO4), and concentrated and the residue purified by CC (AcOEt/hexane
1:9); 11 (0.98 g, 85%). Viscous liquid. [a]2D5 ¼ þ25.6 (c ¼ 0.55, CHCl3). IR (neat):2963, 1725, 1452, 1372,
1224, 1099, 1070. 1H-NMR (500 MHz, CDCl3): 8.02 (dd, J ¼ 8.3, 1.51, 2 H); 7.57 (t, J ¼ 7.55, 1 H); 7.45 (t,
J ¼ 7.55, 2 H); 6.52 – 6.40 (m, 1 H); 6.22 – 6.09 (m, 1 H); 5.95 – 5.87 (m, 1 H); 5.84 – 5.72 (m, 1 H); 5.70 –
5.59 (m, 1 H); 5.57 – 5.48 (m, 1 H); 5.38 – 5.24 (m, 2 H); 5.16 – 5.10 (m, 1 H); 4.69 – 4.61 (m, 1 H); 4.38 –
4.27 (m, 1 H); 2.10 (s, 3 H); 2.06 (s, 3 H). 13C-NMR (75 MHz, CDCl3): 170.3; 169.75; 167.37; 166.47;
133.21; 132.51; 131.93; 131.52; 129.68 (2 C); 128.40 (2 C); 127.24; 119.16; 71.76; 70.69; 68.68; 62.25; 20.77
(2 C). ESI-MS: 413 ([M þ Na]þ).
(ꢀ)-Cleistenolide (¼2,3-Dideoxy-d-arabino-hept-2-enoic Acid d-Lactone 4,6-Diacetate 7-Benzoate;
1). To a degassed soln. of 11 (100 mg, 0.25 mmol) in anh. CH2Cl2 (100 ml) was added Grubbsꢂ second-
generation catalyst (10 mg, 0.012 mmol), and the mixture was refluxed for 5 h. After completion of the
reaction (TLC monitoring), the mixture was filtered, the filtrate concentrated, and the residue purified
by CC (AcOEt/hexane 3 :7): 1 (79 mg, 85%). Colorless solid. M.p. 132 – 1348. [a]2D5 ¼ ꢀ142 (c ¼ 0.4,
CHCl3). IR (KBr): 2963, 1725, 1452, 1372, 1224, 1099, 1070. 1H-NMR (500 MHz, CDCl3): 8.02 (d, J ¼ 7.7,
2 H); 7.57 (t, J ¼ 7.5, 1 H); 7.45 (t, J ¼ 7.6, 2 H); 7.00 (dd, J ¼ 9.6, 6.1, 1 H ); 6.29 (d, J ¼ 9.7, 1 H); 5.52 (ddd,
J ¼ 9.5, 4.0, 2.3, 1 H); 5.42 (dd, J ¼ 6.0, 2.5, 1 H); 4.93 (dd, J ¼ 12.5, 2.0, 1 H); 4.80 (dd, J ¼ 9.6, 2.5,1 H);
4.53 (dd, J ¼ 12.5, 4.4, 1 H); 2.09 (s, MeC¼O); 2.04 (s, MeC¼O). 13C-NMR (75 MHz, CDCl3): 169.9;
169.5; 166.0; 161.1; 139.7; 133.3; 129.7 (2 C); 129.6; 128.5 (2 C); 125.4; 75.5; 67.7; 62.0; 59.7; 20.7; 20.5.
ESI-MS: 385 ([M þ Na]þ). HR-MS: 385.0992 (C18H18NaOþ8 ; calc. 385. 1002).
REFERENCES
[1] D. M. Livermore, Clin. Infect. Dis. 2003, 36, 11; A. Ohno, Infect. Control 2004, 13, 1012; R.
McDaniel, M. Welch, C. R. Hutchinson, Chem. Rev. 2005, 105, 543.
[2] E. Hunt, Drugs Future 2000, 25, 1163; C. Walsh, G. Wright, Chem. Rev. 2005, 105, 391.
˜
[3] B. Siedle, A. J. G. Garcia-Pineres, R. Murillo, J. Schulte-Mçnting, V. Castro, P. Rꢁngeler, C. A.
Klaas, F. B. Da Costa, W. Kisiel, I. Merfort, J. Med. Chem. 2004, 47, 6042.
[4] V. Nair, J. Prabhakaran, T. G. George, Tetrahedron 1997, 53, 15061.
[5] S. Samwel, S. J. M. Mdachi, M. H. H. Nkunya, B. N. Irungu, M. J. Moshi, B. Moulton, B. S. Luisi, Nat.
Prod. Commun. 2007, 2, 737.