S. P. Chavan et al. / Tetrahedron Letters 47 (2006) 9301–9303
9303
(C), 144.4 (C), 137.3 (C), 136.8 (CH), 136.6 (C), 135.6 (C),
130.4 (C), 129.5 (CH), 126.5 (CH), 124.4 (CH), 123.6
(CH), 118.3 (CH), 117.3 (C), 115.8 (CH2), 115.2 (CH),
110.7 (CH2), 58.8 (CH2), 58.6 (CH), 41.0 (CH2), 39.7
(CH2), 26.5 (CH2), 21.5 (CH3), 16.9 (CH2), 12.16 (CH3);
Anal. Calcd for C26H30N2O2S: C, 71.86; H, 6.96; N, 6.45;
S, 7.38. Obtained: C, 71.45; H, 6.72; N, 6.02; S, 6.98.
Compound 30: 1H NMR (200 MHz, CDCl3) d 8.07 (d,
J = 7.9 Hz, 1H), 7.54 (d, J = 8.3 Hz, 2H), 7.32–7.20 (m,
3H), 7.10 (d, J = 8.2 Hz, 2H), 5.56 (br d, 1H), 4.22 (br s,
1H), 3.63–3.56 (m, 1H), 3.32–3.07 (m, 3H), 2.89–2.68 (m,
3H), 2.27 (s, 3H), 2.23–2.18 (m, 1H), 2.02–1.99 (m, 2H),
1.08 (t, J = 7.3 Hz, 3H); 13C NMR (50 MHz, CDCl3) d
144.3 (C), 138.2 (C), 138.0 (C), 136.7 (C), 134.1 (C), 130.9
(C), 129.3 (CH), 126.6 (CH), 124.5 (CH), 124.1 (CH),
120.6 (C), 118.4 (CH), 118 (CH), 116.1 (CH), 57.5 (CH2),
56.1 (CH), 48.2 (CH2), 31.5 (CH2), 27.6 (CH2), 22.4
(CH2), 21.5 (CH3), 12.1 (CH3); Mass (ESI) m/z: 407.54
(M++1); Anal. Calcd for C24H26N2O2S: C, 70.90; H, 6.45;
N, 6.89; S, 7.89. Obtained: C, 70.62; H, 6.32; N, 6.54; S,
7.76. Compound 10: IR (CHCl3) m (cmꢀ1): 3362, 2928. 1H
NMR (200 MHz, CDCl3) d 8.04 (d, J = 8.6, 1H), 7.45 (d,
J = 8.3 Hz, 2H), 7.31–7.20 (m, 3H), 7.05 (d, J = 8.1 Hz,
2H), 3.83 (br d, 1H), 3.71 (dd, J = 5.2 Hz, 11.4 Hz, 1H),
3.59–3.27 (m, 2H), 3.11–2.92 (m, 3H), 2.83–2.52 (m, 4H),
2.26 (s, 3H), 1.94–1.76 (m, 1H), 1.71–1.51 (m, 1H), 0.98 (t,
J = 7.6 Hz, 3H). 13C NMR (125 MHz, CDCl3) d 144.5
(C), 138.4 (C), 133.2 (C), 130.8 (C), 129.2 (CH), 126.6
(CH), 124.8 (CH), 124.4 (CH), 118.4 (CH), 116.4 (CH),
72.1 (C), 71.7 (CH), 61.9 (CH2), 58.9 (CH), 49.9 (CH2),
29.6 (CH2), 27.6 (CH2), 22.9 (CH2), 21.5 (CH3), 7.5 (CH3).
Mass (ESI) m/z: 441.29 (M++1); Anal. Calcd for
C24H28N2O4S: C, 65.43; H, 6.41; N, 6.36; S, 7.28.
Obtained: C, 65.02; H, 6.23; N, 6.02; S, 7.15. Compound
11: IR (CHCl3) m (cmꢀ1): 3437, 1724, 1367. 1H NMR
(400 MHz, CDCl3) d 8.06 (d, J = 7.5 Hz, 1H), 7.45 (d,
J = 8.5 Hz, 2H), 7.32–7.20 (m, 3H), 7.08 (d, J = 8.0 Hz,
2H), 4.21 (br d, 1H), 3.51 (dd, J = 4.5 Hz, 15.3 Hz, 1H),
3.19 (d, J = 12.3 Hz, 1H), 3.14–3.09 (m, 1H), 3.00 (d,
J = 12.3 Hz, 1H), 2.89–2.82 (m, 2H), 2.77–2.71 (m, 1H),
2.61–2.56 (m, 1H), 2.30 (s, 3H), 1.87 (m, 2H), 1.74 (m,
1H), 0.98 (t, J = 7.5 Hz, 3H); 13C NMR (100 MHz,
CDCl3) d 207.8 (C), 144.6 (C), 138.4 (C), 135.9 (C),
133.6 (C), 130.6 (C), 129.9 (C), 129.3 (CH), 126.8 (CH),
126.7 (CH), 125.2 (CH), 124.5 (CH), 122.6 (C), 118.6
(CH), 116.5 (CH), 76.5 (C) 65.2 (CH2), 59.4 (CH3), 49.9
(CH2), 44.3 (CH2), 27.3 (CH2), 22.8 (CH2), 21.5 (CH3), 7.3
(CH3); Mass (ESI) m/z: 439.39 (M++1); Anal. Calcd for
C24H26N2O4S: C, 65.73; H, 5.98; N, 6.39; S, 7.31.
Obtained: C, 65.50; H, 5.88; N, 6.32; S, 7.20. Compound
2: IR (CHCl3) m (cmꢀ1): 3409, 3018, 1716, 1440. 1H NMR
(200 MHz, CDCl3) d 7.82 (br s, 1H), 7.53–7.49 (m, 1H),
7.37–7.34 (m, 1H), 7.23–7.09 (m, 2H), 4.02 (br s, 1H), 3.90
(br d, 1H), 3.22–2.65 (m, 8H), 1.96 (m, 1H), 1.67 (m, 1H),
0.97 (m, 3H); 13C NMR (50 MHz, CDCl3) d 208.5 (C),
136.2 (C), 132.2 (C), 126.7 (C), 121.9 (CH), 119.6 (CH),
118.2 (CH), 111.1 (CH), 108.1 (C), 76.3 (C), 63.1 (CH2),
58.5 (CH), 51.6 (CH2), 41.7 (CH2), 25.4 (CH2), 21.1
(CH2), 7.0 (CH3); Anal. Calcd for C17H20N2O2: C, 71.81;
H, 7.09; N, 9.85. Obtained: C, 71.62; H, 6.95; N, 9.66;
Mass (ESI) m/z: 285.33 (M++1).
required product satisfactorily, we resorted to the two-
step oxidation strategy. Accordingly, olefin 30 was sub-
jected to dihydroxylation employing catalytic OsO4 to
furnish diol 10 in a 60% yield. The secondary hydroxy
group of 10 was easily transformed into ketone 11 under
Swern oxidation conditions.8 The removal of the tosyl
group was achieved by treating compound 11 with
TBAF9 at reflux to furnish intermediate 2,10 which could
easily be transformed to target 1 using a literature pro-
cedure1 (Scheme 2).
In conclusion, a highly functionalised tetracyclic inter-
mediate of mitralactonine was efficiently prepared in a
short synthesis employing RCM as the pivotal step for
the construction of the D ring. High yields along with
simple reaction conditions auger well for the application
of this strategy for the synthesis of this and related
products.
Acknowledgements
P.S. thanks the CSIR, New Delhi (India), for the award
of fellowship. Funding from DST (CSIR), New Delhi, is
gratefully acknowledged.
References and notes
1. Takayama, H.; Kurihara, M.; Kitajima, M.; Said, I. M.;
Aimi, N. J. Org. Chem. 1999, 64, 1772.
2. (a) Grubbs, R. H. Handbook of Metathesis. In Applications
in Organic Synthesis; WILEY-VCH, 2003; Vol. 2; (b) Fu,
G. C.; Grubbs, R. H. J. Am. Chem. Soc. 1992, 114, 7324.
3. (a) Chavan, S. P.; Pasupathy, K.; Venkatraman, M. S.;
Kale, R. R. Tetrahedron Lett. 2004, 45, 6879; (b) Chavan,
S. P.; Praveen, C. Tetrahedron Lett. 2005, 46, 1939; (c)
Chavan, S. P.; Thakkar, M.; Jogdand, G. F.; Kalkote, U.
4. (a) Deiters, A.; Martin, S. F. Org. Lett. 2002, 4, 3243, and
references therein; (b) Deiters, A.; Pettersson, M.; Martin,
S. F. J. Org. Chem. 2006, 71, 6547.
5. Vercauteren, J.; Lavaud, C.; Levy, J.; Massiot, G. J. Org.
Chem. 1984, 49, 2278.
6. Srinivasan, N. S.; Lee, D. G. Synthesis 1979, 520.
7. Minato, M.; Yamamoto, K.; Tsuji, J. J. Org. Chem. 1990,
55, 766.
8. Mancuso, A. J.; Huang, S. H.; Swern, D. J. Org. Chem.
1978, 43, 2480.
9. Itoh, T.; Yokoya, M.; Miyauchi, K.; Ohsawa, A. Org.
Lett. 2003, 5, 4301.
10. Spectral data of compound 40: IR (CHCl3) m (cmꢀ1): 3019,
1
1371; H NMR (200 MHz, CDCl3) d 8.12 (d, J = 7.2 Hz,
1H), 7.56 (d, J = 8.3 Hz, 2H), 7.30–7.20 (m, 3H), 7.12 (d,
J = 7.9 Hz, 2H), 6.12–5.91 (m, 1H), 5.17–5.02 (m, 2H),
4.85 (m, 2H), 4.20 (br d, 1H), 3.24–2.63 (m, 6H), 2.50–2.35
(m, 2H), 2.31 (s, 3H), 2.20–2.10 (m, 2H), 1.07 (t,
J = 7.3 Hz, 3H). 13C NMR (50 MHz, CDCl3) d 149.2