M. K. Gurjar et al. / Tetrahedron Letters 44 (2003) 2873–2875
2875
ratio. Surprisingly and gratifyingly, attempted MEM-
deprotection using TiCl4 also resulted in debenzyla-
tion,13 thus furnishing microcarpalide 1 in 76% yield.
The spectroscopic and analytical data {[h]2D5=−23.2 (c
0.7, MeOH)} of compound 1 were in agreement with
the reported data.1,3
Am. Chem. Soc. 1993, 115, 5254–5266; (b) Coutrot, P.;
Grison, C.; Lecouvey, M. Bull. Soc. Chim. Fr. 1997, 134,
27–46.
8. Smith, A. B., III; Qiu, Y.; Jones, D. R.; Kobayashi, K. J.
Am. Chem. Soc. 1995, 117, 12011–12012.
9. Rama Rao, A. V.; Reddy, E. R.; Joshi, B. V.; Yadav, J.
S. Tetrahedron Lett. 1987, 28, 6497–6500.
In conclusion, we have developed a total synthesis of
microcarpalide using both the chiral pool approach and
an asymmetric dihydroxylation which is characterized
by considerable flexibility for the construction of
related unnatural analogues for structure activity stud-
ies. Work in this direction is progressing in our
laboratory.
10. Monti, H.; Leandri, G.; Klos-Ringuet, M.; Corriol, C.
Synth. Commun. 1983, 13, 1021–1026.
11. Dalcanale, E.; Montanari, F. J. Org. Chem. 1986, 51,
567–569.
12. Spectral data of 3: 1H NMR (200 MHz, CDCl3) l
1.61–1.80 (m, 1H), 1.83–1.99 (m, 1H), 2.33–2.44 (m, 2H),
3.52 (ddd, 1H, J=9.3, 6.0, 3.7 Hz), 3.90 (t, 1H, J=6.5
Hz), 4.38 (d, 1H, J=12.2 Hz), 4.52 (d, 1H, J=11.3 Hz),
4.64 (d, 1H, J=12.1 Hz), 4.76 (d, 1H, J=11.3 Hz), 5.32
(br. dd, 1H, J=18.4, 1.7 Hz), 5.36 (br. dd, 1H, J=9.1,
1.8 Hz), 5.81 (br. ddd, 1H, J=18.3, 10.9, 7.5 Hz), 7.25–
7.33 (m, 10H). 13C NMR (50 MHz, CDCl3) l 26.3, 30.9,
70.5, 73.3, 80.2, 82.7, 96.1, 118.8, 127.4, 127.6, 127.9,
128.2, 135.1, 138.5, 138.6, 178.7. Anal. calcd for
C21H24O4: C, 74.09; H, 7.11. Found: C, 74.16; H, 7.49.
13. (a) Corey, E. J.; Gras, J. L.; Ulrich, P. Tetrahedron Lett.
1976, 11, 809–812; (b) Bhatt, M. V.; Kulkarni, S. V.
Synthesis 1983, 249–334.
Acknowledgements
R.N. thanks CSIR for financial support in the form of
a research fellowship.
References
14. (a) Spectral data of 18: 1H NMR (500 MHz, CDCl3) l
0.87 (t, 3H, J=6.9 Hz), 1.21–1.34 (m, 8H), 1.46–1.54 (m,
2H), 1.67–1.74 (m, 1H), 1.88–1.95 (m, 1H), 2.25–2.46 (m,
4H), 3.37 (s, 3H), 3.49–3.54 (m, 3H), 3.58 (br. ddd, 1H,
J=6.2, 5.6, 4.3 Hz), 3.66–3.73 (m, 2H), 3.87 (t, 1H,
J=6.7 Hz), 4.38 (d, 1H, J=11.9 Hz), 4.52 (d, 1H,
J=11.4 Hz), 4.62 (d, 1H, J=11.9 Hz), 4.71–4.77 (m, 3H),
4.99–5.07 (m, 3H), 5.27–5.33 (m, 2H), 5.71 (dddd, 1H,
J=17.1, 10.1, 7.6, 6.6 Hz), 5.80 (ddd, 1H, J=17.3, 10.6,
7.6 Hz), 7.25–7.30 (m, 10H). 13C NMR (125 MHz,
CDCl3) l 14.12, 22.65, 25.41, 26.33, 29.47, 30.52, 31.81,
34.71, 59.00, 67.49, 70.65, 71.83, 73.41, 78.13, 80.17,
82.60, 96.23, 117.62, 118.85, 127.49, 127.55, 127.73,
127.93, 128.33, 134.08, 135.23, 138.56, 138.75, 172.84.
Anal. calcd for C36H52O7: C, 72.45; H, 8.78. Found: C,
72.08; H, 9.13. (b) Spectral data of 19: 1H NMR (500
MHz, CDCl3) l 0.87 (t, 3H, J=6.9 Hz), 1.26–1.32 (m,
8H), 1.54–1.59 (m, 3H), 2.02 (ddd, 1H, J=15.2, 10.6, 6.2
Hz), 2.17 (ddd, 1H, J=14.7, 10.6, 1.4), 2.24–2.30 (m,
2H), 2.61 (dd, 1H, J=14.7, 9.2 Hz), 3.38 (s, 3H), 3.54–
3.56 (m, 2H), 3.67–3.78 (m, 4H), 4.07 (br. d, 1H, J=4.5
Hz), 4.47 (d, 1H, J=11.9 Hz), 4.48 (d, 1H, J=12.5 Hz),
4.54 (d, 1H, J=11.9 Hz), 4.65 (d, 1H, J=12.5 Hz),
4.78–4.81 (m, 2H), 5.15 (dt, 1H, J=9.2, 4.6 Hz), 5.64 (dd,
1H, J=15.8, 2.1 Hz), 5.64–5.73 (m, 1H), 7.28–7.35 (m,
10H). 13C NMR (125 MHz, CDCl3) 14.01, 22.56, 25.03,
29.39, 31.15, 31.71, 36.06, 59.00, 67.40, 71.34, 71.54,
71.78, 78.19, 95.36, 126.47, 127.22, 127.52, 127.61, 128.30,
128.36, 131.69, 138.45, 138.79, 175.17. Anal. calcd for
C34H48O7: C, 71.80; H, 8.51. Found: C, 71.97; H, 8.98.
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3. During our work in progress, Marco and co-workers
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RCM as the key transformation. See: Murga, J.; Falmoir,
E.; Garcia-Fortanet, J.; Carda, M.; Marco, J. A. Org.
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4. (a) Sharpless, K. B.; Amberg, W.; Bennani, Y. L.;
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6. Spectral data of 2: 1H NMR (200 MHz, CDCl3) l 0.90 (t,
3H, J=6.6 Hz), 1.21–1.38 (m, 8H), 1.44–1.61 (m, 2H),
2.10–2.39 (m, 2H), 2.81 (s, 1H, -OH), 3.37–3.49 (m, 1H),
3.39 (s, 3H, -OMe), 3.52–3.84 (m, 5H), 4.70–4.87 (m, 2H,
-OCH2O-), 5.06–5.17 (m, 2H), 5.88 (br. ddt, 1H, J=17.4,
10.6, 7.0 Hz). 13C NMR (50 MHz, CDCl3) l 14.1, 22.6,
25.1, 29.4, 30.8, 31.7, 37.8, 58.9, 67.6, 71.7, 72.0, 82.4,
95.9, 117.1, 134.9. Anal. calcd for C15H30O4: C, 65.66; H,
11.02. Found: C, 65.07; H, 10.83.
7. (a) Moore, B. S.; Cho, H.; Casati, R.; Kennedy, E.;
Reynolds, K. A.; Mocek, U.; Beale, J. M.; Floss, H. G. J.