S. P. Chavan et al. / Tetrahedron Letters 48 (2007) 535–537
537
25
16. Spectral data for compound 11: Specific rotation: ½aꢁD
ꢀ37.91 (c 1.5, CHCl3). IR (CHCl3) mmax (cmꢀ1): 3411,
1621, 1589. 1H NMR (CDCl3, 200 MHz): d 1.19 (d,
J = 7.0 Hz, 3H); 1.52–1.66 (m, 2H); 1.55 (s, 3H); 1.66 (s,
3H); 1.80–1.91 (m, 2H); 2.20 (s, 3H); 2.53–2.64 (m, 1H);
5.05 (apparent triplet, J = 7.1 Hz, 1H); 6.56–6.65 (m, 2H);
6.98 (d, J = 7.7 Hz, 1H). 13C NMR (CDCl3, 50 MHz): d
15.5 (CH3); 17.8 (CH3); 22.5 (CH3); 25.8 (CH3); 26.2
(CH2); 38.5 (CH2); 39.1 (CH); 113.6 (CH); 119.4 (CH);
120.9 (C); 124.8 (CH); 130.8 (CH); 131.2 (C); 147.0 (C);
153.7 (C). MS-ESI m/z: 218 (M)+. Analysis calculated for
C15H22O: C, 82.52; H, 10.16. Found: C, 82.29; H, 10.35.
(+)-citronellal, employing intramolecular Friedel–Crafts
acylation as the key step.
Acknowledgements
We profoundly thank Takasago International Corpora-
tion, Japan, for a generous gift of (R)-(+)-citronellal.
M.R.T. thanks CSIR for
a fellowship. Funding
from DST, New Delhi, India, to S.P.C. is gratefully
acknowledged.
25
Compound 7: Specific rotation: ½aꢁD ꢀ37.23 (c 2, CHCl3).
IR (CHCl3) mmax (cmꢀ1): 3020, 2960, 1705, 1644, 1612,
1
1581. H NMR (CDCl3, 200 MHz): d 1.25 (d, J = 6.7 Hz,
3H); 1.23 (t, J = 7.1 Hz, 3H); 1.60–1.73 (m, 2H); 1.86 (d,
J = 1.3 Hz, 3H); 2.17 (s, 3H); 2.28–2.50 (m, 2H); 2.57–
2.71 (m, 1H); 3.82 (s, 3H); 4.14 (q, J = 7.1 Hz, 2H); 5.87
(triplet of doublets, J = 7.6, 1.4 Hz, 1H); 6.64–6.70 (m,
2H); 7.03 (d, J = 7.5 Hz, 1H). 13C NMR (CDCl3,
50 MHz): d 14.1 (CH3); 15.8 (CH3); 20.6 (CH3); 22.2
(CH3); 27.9 (CH2); 38.0 (CH2); 39.7 (CH); 55.2 (CH3);
60.0 (CH2); 108.9 (CH); 118.6 (CH); 123.9 (C); 127.2 (C);
130.4 (CH); 142.5 (CH); 146.2 (C); 157.6 (C); 168.1 (C).
MS-ESI m/z: 291 (M+1)+. Analysis calculated for
C18H26O3: C, 74.45; H, 9.02. Found: C, 74.36; H, 8.81.
References and notes
1. Bohlmann, F.; Zdero, C. Chem. Ber. 1977, 110, 468–473.
2. (a) Joseph-Nathan, P.; Hernandez, J. D.; Roman, L. U.;
Garcia, G. E.; Mendoza, V.; Mendoza, S. Phytochemistry
1982, 21, 1129–1132; (b) Joseph-Nathan, P.; Hernandez, J.
D.; Roman, L. U.; Garcia, G. E.; Mendoza, V. Phyto-
chemistry 1982, 21, 669–672; (c) Garcia, G. E.; Mendoza,
V.; Guzman, B. A. J. Nat. Prod. 1988, 51, 150–151.
3. (a) Joseph-Nathan, P.; Hernandez-Medel, M. del R.;
Martinez, E.; Rojas-Gardida, M.; Cerda, C. M. J. Nat.
Prod. 1988, 51, 675–689; (b) Garcia, G. E.; Mendoza, V.;
Guzman, B. A. J. Nat. Prod. 1987, 50, 1055–1058.
4. McEnroe, F. J.; Fenical, W. Tetrahedron 1978, 34, 1661–
1664.
5. Chavan, S. P.; Ravindranathan, T.; Dhondge, V. D.; Patil,
S. S.; Rao, T. S.; Govande, C. A. Tetrahedron: Asymmetry
1997, 8, 2517–2518.
6. Chavan, S. P.; Thakkar, M.; Kharul, R. K.; Pathak, A. B.;
Bhosekar, A. V.; Bhadbhade, M. V. Tetrahedron 2005, 61,
3873–3879.
7. (a) Villagomez-Ibarra, R.; Joseph-Nathan, P. Tetrahedron
Lett. 1994, 35, 4771–4772; (b) Grimm, E. L.; Levac, S.;
Coutu, M. L. Tetrahedron Lett. 1994, 35, 5369–5372; (c)
Villagomez-Ibarra, R.; Alvarez-Cisneros, C.; Joseph-
Nathan, P. Tetrahedron 1995, 51, 9285–9300; (d) Cova-
rrubias-Zuniga, A.; Cantu, F.; Maldonado, L. A. J. Org.
Chem. 1998, 63, 2918–2921; (e) Bhowmik, D. R.; Ven-
kateswaran, R. V. Tetrahedron Lett. 1999, 40, 7431–7433.
8. Chavan, S. P.; Thakkar, M.; Jogdand, G. F.; Kalkote, U.
R. J. Org. Chem. 2006, 71, 8986–8988.
9. (a) Ghisalberti, E. L.; Jeferies, P. R.; Stuart, A. D. Aust. J.
Chem. 1979, 32, 1627–1630; (b) Hagiwara, H.; Tomoyuki,
O.; Ono, H.; Kamat, V. P.; Hoshi, T.; Suzuki, T.; Ando,
M. J. Chem. Soc., Perkin Trans. 1 2002, 895–900.
10. Rubottom, G. M.; Gruber, J. M. J. Org. Chem. 1978, 43,
1599–1602.
25
Compound 6: Specific rotation: ½aꢁD ꢀ220.13 (c 1.7,
CHCl3). IR (CHCl3) mmax (cmꢀ1): 3009, 2959, 1710,
1624, 1600. 1H NMR (CDCl3, 200 MHz): d 1.35 (d,
J = 6.9 Hz, 3H); 1.58–2.0 (m, 4H); 2.02 (s, 3H); 2.19 (s,
3H); 3.08–3.27 (m, 1H); 3.86 (s, 3H); 6.44 (triplet of
doublets, J = 9.0, 1.4 Hz, 1H); 6.64 (s, 1H); 7.41 (d,
J = 0.8 Hz, 1H). 13C NMR (CDCl3, 50 MHz): d 15.6
(CH3); 18.2 (CH3); 21.2 (CH3); 25.5 (CH2); 31.7 (CH);
39.3 (CH2); 55.3 (CH3); 104.7 (CH); 124.5 (C); 132.2
(CH); 135.0 (C); 138.9 (CH); 141.3 (C); 143.0 (C); 160.6
(C); 195.4 (C). MS-ESI m/z: 245 (M+1)+ Analysis
calculated for C16H20O2: C, 78.65; H, 8.25. Found : C,
78.79; H, 8.56. Compound 2: mp: 157–158 °C {lit.2 mp
25
157–158 °C}. Specific rotation: ½aꢁD +850 (c 1, CHCl3)
25
{lit.2 ½aꢁD +854 (c 1, CHCl3)}. IR (CHCl3) mmax (cmꢀ1):
3596, 3364, 3020, 2969, 1638, 1581. 1H NMR (CDCl3,
200 MHz): d 1.24 (d, J = 6.8 Hz, 3H); 1.45–1.61 (m, 1H);
2.02 (d, J = 1.2 Hz, 3H); 2.1–2.25 (m, 2H); 2.25 (s, 3H);
2.45–2.59 (m, 1H); 2.88–2.99 (m, 1H); 6.08 (br s, 1H); 6.79
(s, 1H); 7.03 (s, 1H); 7.10 (br s, 1H). 13C NMR (CDCl3,
50 MHz): d 15.3 (CH3); 19.5 (CH3); 20.6 (CH3); 33.4
(CH); 39.1 (CH2); 42.0 (CH2); 111.4 (CH); 121.7 (C);
129.2 (C); 133.4 (CH); 136.3 (C); 139.7 (CH); 144.1 (C);
155.1 (C); 204.8 (C). Compound 1: mp: 85 °C, {lit.2 89–
90 °C, crystallised from hexane/acetone}. Specific rota-
25
tion: ½aꢁD ꢀ168 (c 1.73, CHCl3) {lit.2 ꢀ173 (c 1.73,
1
CHCl3)}. IR (CHCl3) mmax (cmꢀ1): 3602, 3369, 1619. H
11. Mancuso, A. J.; Huang, S. L.; Swern, D. J. Org. Chem.
1978, 43, 2480–2482.
12. Ando, K. J. Org. Chem. 1997, 62, 1934–1939.
13. McIntyre, D.; Proctor, G. R.; Rees, L. J. Chem. Soc. (C)
1966, 985–989.
14. Luche, J. L.; Hahn, L. R.; Crabbe, P. J. Chem. Soc.,
Chem. Commun. 1978, 601–602.
15. (a) Babler, J. H.; Coghlan, J. Synth. Commun. 1976, 6,
469–474; (b) Dauben, W. G.; Michno, D. M. J. Org.
Chem. 1977, 42, 682.
NMR (CDCl3, 200 MHz): d 1.08–1.13 (m, 1H); 1.31 (d,
J = 7.0 Hz, 3H); 1.74 (s, 3H); 1.57–1.80 (m, 3H); 2.20 (s,
3H); 3.04 (d, J = 18.3 Hz, 1H); 3.11–3.20 (m, 1H); 3.53 (d,
J = 18.3 Hz, 1H); 4.53 (br s, 1H); 5.36 (t, J = 7.0 Hz, 1H);
6.60 (s, 1H); 6.88 (s, 1H). 13C NMR (CDCl3, 50 MHz): d
15.3 (CH3); 19.4 (CH3); 23.8 (CH2); 26.5 (CH3); 33.1
(CH); 40.1 (CH2); 41.7 (CH2); 111.2 (CH); 120.1 (C);
123.5 (CH); 130.7 (C); 131.9 (CH); 137.7 (C); 144.1 (C);
153.0 (C).