P. Radha Krishna, R. Srinivas / Tetrahedron Letters 48 (2007) 2013–2015
2015
O
1. Oxidation
example, the coupling constant (J = 11.3 Hz) of the ole-
finic protons confirmed the (Z)-geometry of the olefin.
Finally, acid-catalyzed (PTSA) desilylation followed by
2. Ph3PCHCOOEt,
benzene, reflux
4.Sharpless
epoxidation
OH
OH
OH
3
3
3
3. LAH/AlCl3, THF,
0-r t
OTBS
OR'
6
9. Oxidation
10. Wittig
5. Red-Al, THF
concomitant lactone cyclization yielded target com-
OR
3
25
pound 1 (65%). Mp 66–68 ꢁC; ½aꢁD +51.70 (c 0.25,
25
3
9a
6. BzCl, Et3N,
CH2Cl2,rt
7. TBSCl, Imidazole,
CH2Cl2, rt
R' = H, R = Bz
R' = TBS, R = H
CHCl3); {lit.3 mp 74 ꢁC; ½aꢁD +59.00 (c 2.00, CHCl3)}.
8. Base
The physical and spectroscopic data of 1 were identical
to the reported values of the natural product.
10. Rychnovsky, S. D.; Skalitzky, D. J. Tetrahedron Lett.
1990, 31, 945–948.
In conclusion, the first stereoselective synthesis of 1 has
been accomplished by a convergent strategy wherein one
of the advanced intermediates was accessed by iterative
Jacobsen’s hydrolytic kinetic resolutions with two enan-
tiomeric salens for installing the 1,3-anti-polyol sys-
tem.12 The synthesis reported herein establishes the
absolute stereochemistry of the isolated natural product.
11. Still, W. C.; Gennari, C. Tetrahedron Lett. 1983, 24, 4405–
4408.
12. Spectral data of selected compounds. Compound 9a: light
25
yellow liquid; ½aꢁD +53.80 (c 0.35, CHCl3); 1H NMR
(200 MHz, CDCl3): d 7.26–7.10 (m, 5H, Ar-H), 5.89–5.68
(m, 1H, –CH@CH2), 5.14–5.04 (m, 2H, CH2@CH–), 3.65–
3.54 (m, 1H, –CH–OH), 2.61 (dd, J = 6.9, 14.7 Hz, 2H,
Ph–CH2–), 2.32–2.02 (m, 2H, –CH2–CH@CH2), 1.72–1.57
(m, 2H, –CH2), 1.53–1.40 (m, 4H, 2 · –CH2–); 13C NMR
(100 MHz, CDCl3): 142.4, 134.7, 128.2, 125.5, 117.9, 70.4,
41.8, 36.5, 35.8, 31.3, 25.2; IR (neat): 3449, 2912, 2857,
Acknowledgement
1223 cmꢀ1
;
LCMS; 227 (M+Na)+. Anal. Calcd for
C14H20O: C, 82.30; H, 9.87. Found: C, 82.32; H, 9.83.
One of the authors (R.S.) thanks the UGC, New Delhi,
for financial support in the form of a fellowship.
25
Compound 11: Colorless liquid; ½aꢁD ꢀ62.25 (c 0.60,
CHCl3); 1H NMR (300 MHz, CDCl3): d 7.25–7.19 (m,
5H, Ar-H), 7.14–7.09 (m, 2H, Ar-H), 6.79 (d, J = 8.8 Hz,
2H, Ar-H), 5.67–5.42 (m, 2H, –CH@CH–), 4.41 (s, 2H,
Ar-CH2–O–), 4.22 (q, J = 6.43, 12.07 Hz, 1H, –CH–OH),
3.78 (s, 3H, –OCH3), 3.76–3.51 (m, 4H, 2 · –CH–OH,
–CH2–OPMB), 2.58 (t, J = 7.24, 15.29 Hz, 2H, Ph–CH2–),
2.30 (m, 2H, –CH2–CH@CH–), 1.74 (m, 2H, –CH2–),
1.64–1.33 (m, 8H, 4 · –CH2–), 1.28 (2s, 6H, 2 · –CH3);
13C NMR (75 MHz, CDCl3): 159.1, 142.9, 134.8, 130.1,
129.2, 128.2, 128.1, 126.6, 125.5, 113.7, 100.0, 72.8, 71.4,
67.9, 66.4, 66.2, 55.1, 38.4, 38.0, 36.6, 35.7, 35.6, 31.3, 24.9,
References and notes
1. Hoffmann, H. M. R.; Rabe, J. Angew. Chem., Int. Ed.
Engl. 1985, 24, 94–110.
2. (a) Pereda-Miranda, R.; Fragoso-Serrano, M.; Cerda-
´
Garcıa-Rojas, C. M. Tetrahedron 2001, 57, 47–53; (b)
´
Carda, M.; Rodrıguez, S.; Segovia, B.; Marco, J. A. J.
´
Org. Chem. 2002, 67, 6560–6563; (c) Carda, M.; Gonzalez,
24.8, 24.7; IR (neat): 3447, 2933, 2858, 1611, 1246 cmꢀ1
;
´
F.; Castillo, E.; Rodrıguez, S.; Marco, J. A. Eur. J. Org.
LCMS; 505 (M + Na)+. Anal. Calcd for C30H42O5: C,
Chem. 2002, 2649–2655; (d) Murga, J.; Falomir, E.;
74.65; H, 8.77. Found: C, 74.61; H, 8.72. Compound 2:
´
Garcıa-Fortanet, J.; Carda, M.; Marco, J. A. Org. Lett.
25
Thick syrup; ½aꢁD ꢀ29.20 (c 0.30, CHCl3); 1H NMR
´
2002, 4, 3447–3449; (e) Carda, M.; Rodrıguez, S.; Castillo,
E.; Bellido, A. A.; Dıaz-Oltra, S.; Marco, J. A. Tetra-
hedron 2003, 59, 857–864.
(300 MHz, CDCl3): d 7.26–7.09 (m, 5H, Ar-H), 6.32–6.24
(m, 1H, –CH@CH–COOMe), 5.81 (d, J = 11.3 Hz, 1H,
–CH@CH–COOMe), 5.61–5.41 (m, 2H, CH@CH), 4.20
(q, J = 5.28 Hz, 1H, –CH–OTBS), 3.80–3.6 (m, 2H, 2 ·
–CH–OH), 3.68 (s, 3H, –OCH3), 2.82 (t, J = 6.40,
12.84 Hz, 2H, –HOCH2–CH2–CH@CH),2.59 (t, J =
7.55, 15.86 Hz, 2H, Ph–CH2), 2.24–2.09 (m, 2H,
–CH2–), 1.66–1.36 (m, 6H, 3 · –CH2–), 1.28 (s, 6H, 2 ·
–CH3), 0.87 (s, 9H, tBu), 0.02 (s, 6H, 2 · CH3–Si); 13C
NMR (75 MHz, CDCl3): d 166.9, 146.5, 135.3, 128.2,
128.1, 126.4, 125.7, 120.2, 100.3, 72.3, 68.8, 66.4, 66.3,
50.9, 38,5, 38.1, 37.5, 35.8, 35.6, 31.3, 25.8, 25.0, 24.7, 18.1,
´
3. Raoelison, G. E.; Terreaux, C.; Queiroz, E. F.; Zsila, F.;
Simonyi, M.; Antus, S.; Randriantsova, A.; Hostettmann,
K. Helv. Chim. Acta 2001, 84, 3470–3476.
4. Chandrasekhar, S.; Narsihmulu, Ch.; Sultana, S.; Srini-
vasa Reddy, M. Tetrahedron Lett. 2004, 45, 9299–9301.
5. (a) Radha Krishna, P.; Narasimha Reddy, P. V. Tetra-
hedron Lett. 2006, 47, 7473–7476; (b) Radha Krishna, P.;
Narasimha Reddy, P. V. Tetrahedron Lett. 2006, 47, 4627–
4630; (c) Radha Krishna, P.; Ramana Reddy, V. V.
Tetrahedron Lett. 2005, 46, 3905–3907; (d) Radha
Krishna, P.; Ramana Reddy, V. V.; Sharma, G. V. M.
Synthesis 2004, 2107–2114; (e) Radha Krishna, P.; Nar-
singam, M.; Kannan, V. Tetrahedron Lett. 2004, 45, 4773–
4775.
ꢀ4.3, ꢀ4.8; IR (neat): 2929, 2856, 1724, 1643, 1220 cmꢀ1
;
LCMS; 553 (M + Na)+. Anal. Calcd for C31H50O5Si: C,
70.14; H, 9.49. Found: C, 70.10; H, 9.51. Compound 1:
25
White solid, mp: 66–68 ꢁC; ½aꢁD +51.70 (c 0.25, CHCl3);
1H NMR (300 MHz, CDCl3): d 7.27–7.10 (m, 5H, Ar-H),
6.88–6.80 (m, 1H, –CH@CH–CO), 6.01 (d, J = 9.8 Hz,
1H, –CH@CH–CO), 5.85 (ddd, J = 7.5, 7.5, 14.4 Hz, 1H,
–CH@CH–), 5.64 (dd, J = 6.5, 15.1 Hz, 1H, –CH@CH–),
4.86 (q, J = 7.5, 14.4 Hz, 1H, –CH–O–), 4.05–3.95 (m, 1H,
–CH–OH), 3.94–3.85 (m, 1H, –CH–OH), 2.59 (t, J = 7.5,
15.1 Hz, 2H, –CH2–Ph), 2.45–2.38 (m, 2H, –CH2–), 2.29–
2.27 (m, 2H, –CH2–), 1.68–1.58 (m, 2H, –CH2–), 1.54–1.39
(m, 6H, 3 · CH2); 13C NMR (75 MHz, CDCl3): d 164.1,
144.7, 142.4, 131.4, 129.7, 128.3, 128.2, 125.6, 121.4, 77.8,
69.2, 68.2, 42.0, 40.3, 37.3, 35.8, 31.3, 29.7, 25.4; IR (neat):
3414, 2924, 2854, 1708, 1248 cmꢀ1; LCMS; 367 (M+Na)+.
Anal. Calcd for C21H28O4: C, 73.23; H, 8.19. Found: C,
73.30; H, 8.17.
6. Ramana, C. V.; Raghupathi, N.; Gurjar, M. K.; Chorgh-
ade, M. S. Tetrahedron Lett. 2005, 46, 4073–4075.
7. (a) Tokunaga, M.; Larrow, J. F.; Kakiuchi, F.; Jacobsen,
E. N. Science 1997, 277, 936–938; (b) Schaus, S. E.;
Brandes, B. D.; Larrow, J. F.; Tokunaga, M.; Hansen, K.
B.; Gould, A. E.; Furrow, M. E.; Jacobsen, E. N. J. Am.
Chem. Soc. 2002, 124, 1307–1315.
25
8. Compound 8 spectral data: ½aꢁD +12.70 (c 1.00, CHCl3); 1H
NMR (300 MHz, CDCl3): d 7.26–7.10 (m, 5H, Ar-H),
2.86–2.80 (m, 1H, H-2), 2.68 (dd, J = 5.28, 9.06 Hz, 1H,
H-1), 2.61 (t, J = 6.79 Hz, 2H, Ar-CH2), 2.39 (dd,
J = 2.26, 5.28 Hz, 1H, H-1), 1.73–1.63 (m, 2H, CH2),
1.59–1.45 (m, 4H, 2 · CH2).
9. Compound 9a was independently synthesized as follows: