782
Gudipati, Bajpai, Curran:
69.8, 72.7, 72.9, 108.8, 113.9, 129.3, 130.2, 159.3, 209.5. IR (n eat): 3466, 2952, 2931, 1708,
1514, 1302, 1090, 777. HRMS (ES) for C27H46NaO7Si (M + Na)+: calculated 533.2911, foun d
533.2886.
(3S,5S,7R)-5,7-Bis[(tert-butyldim eth ylsilyl)oxy]-8-[(4S)-2,2-dim eth yl-1,3-dioxolan -4-yl]-
1-[(4-m eth oxyben zyl)oxy]octan -3-ol (26)
To a solution of 25 (88 m g, 0.17 m m ol) in aceton itrile (0.54 m l) at –25 °C, a solution of
(CH3)4NBH(OAc)3 (68 m g, 0.26 m m ol) in acetic acid (0.1 m l) was added. Th e reaction m ix-
ture was stirred at th at tem perature for 48 h , quen ch ed with aqueous sodium potassium
tartarate (1.0 M, 0.8 m l), diluted with eth yl acetate an d n eutralized with sodium h ydrogen
carbon ate. Th e aqueous layer was extracted with eth yl acetate; th e com bin ed organ ic layers
were dried over an h ydrous MgSO4 an d con cen trated to yield th e title com poun d (76 m g,
86%) as an oil. Crude 26 was taken to th e n ext step with out furth er purification . 1H NMR
(500 MHz, CDCl3): 0.12 (s, 3 H), 0.14 (s, 3 H), 0.90 (s, 9 H), 1.34 (s, 3 H), 1.38 (s, 3 H),
1.50–1.62 (m , 3 H), 1.66–1.75 (m , 2 H), 1.78–1.92 (m , 3 H), 3.48 (t, J = 8.0, 1 H), 3.57 (brs,
1 H), 3.60–3.71 (m , 2 H), 3.80 (s, 3 H), 3.89 (brs, 1 H), 4.05 (dd, J = 7.8, 6.0, 1 H), 4.09–4.24
(m , 3 H), 4.26–4.34 (m , 1 H), 4.45 (s, 2 H), 6.87 (d, J = 8.7, 2 H), 7.24 (d, J = 8.7, 2 H).
13C NMR (76 MHz, CDCl3): –4.8, –4.4, 18.0, 25.9, 27.1, 36.9, 40.4, 43.1, 43.9, 55.3, 66.0,
68.4, 68.8, 69.3, 69.9, 70.1, 72.8, 73.0, 108.9, 113.9, 129.3, 130.3, 159.4. IR (n eat): 3449,
2984, 2934, 2857, 1613, 1514, 1249. HRMS (EI) for C27H48NaO7Si (M + Na)+: calculated
535.3067, foun d 535.3072.
(4S)-2,2-Dim eth yl-4-{(2S,4S,6R)-2,4,6-tris[(tert-butyldim eth ylsilyl)oxy]-
8-[(4-m eth oxyben zyl)oxy]octyl}-1,3-dioxolan e (27)
To a solution of 26 (44.0 m g, 0.0858 m m ol) in dich lorom eth an e (5 m l) at 0 °C, TBSOTf
(46.5 m g, 0.176 m m ol) an d 2,6-lutidin e (54.3 m g, 0.506 m m ol) were added. Th e reaction
m ixture was stirred at th at tem perature for 1 h followed by quen ch in g with water. Th e
aqueous layer was extracted with dich lorom eth an e an d th e com bin ed organ ic layers were
dried over MgSO4 an d con cen trated. Purification of th e crude reaction m ixture by flash col-
um n ch rom atograph y (silica gel, 10% eth yl acetate in h exan es) gave 27 (50 m g, 80%) as
a clear oil. 1H NMR (300 MHz, CDCl3): 0.07 (s, 18 H), 0.88 (s, 18 H), 0.89 (s, 9 H), 1.33 (s,
3 H), 1.38 (s, 3 H), 1.48–1.87 (m , 8 H), 3.42–3.52 (m , 3 H), 3.75–3.84 (m , 4 H), 3.85–3.94
(m , 2 H), 4.00–4.04 (m , 1 H), 4.13–4.26 (m , 1 H), 4.41 (s, 2 H), 6.87 (d, J = 8.8, 2 H), 7.25 (d,
J = 7.7, 2 H). 13C NMR (75 MHz, CDCl3): –4.4, –4.2, –4.1, –3.7, –3.5, 18.1, 26.0, 27.2, 37.9,
41.3, 46.3, 47.3, 55.3, 66.7, 67.4, 67.5, 67.7, 70.0, 72.7, 108.6, 113.8, 129.3, 130.8, 159.1.
IR (n eat): 2953, 2857, 1511, 1250. HRMS (EI) for C39H76NaO7Si3 (M + Na)+: calculated
129.0552, foun d 129.0550.
REFERENCES
1. a) Kamiyama T., Itezono Y., Umino T., Satoh T., Nakayama N., Yokose K.: J. Antibiot.
1993, 46, 1047; b) Kamiyama T., Umino T., Fujisaki N., Fujimori K., Satoh T., Yamashita Y.,
Ohshima S., Watanabe J., Yokose K.: J. Antibiot. 1993, 46, 1039.
2. Kobayashi Y., Czechtizky W., Kishi Y.: Org. Lett. 2003, 5, 93.
3. Lira R., Roush W. R.: Org. Lett. 2007, 9, 533.
4. BouzBouz S., Cossy J.: Org. Lett. 2004, 6, 3469.
Collect. Czech. Chem. Commun. 2009, Vol. 74, No. 5, pp. 771–783