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S. Datta et al. / Tetrahedron Letters 49 (2008) 2935–2938
(q), 118.7 (CH), 124.4 (CH), 126.2 (CH), 128.0 (CH), 128.6 (CH),
129.0 (CH), 139.5 (q), 148.9 (q). Calcd for C23H25NO5: C, 69.86; H,
6.37; N, 3.54. Found: C, 69.62; H, 6.65; N, 3.27. Compound 4e: [a]D
À194.7 (c 0.65, CHCl3); IR (neat): 2986, 2938, 1593, 1487, 1447, 1376,
1260, 1214, 1165, 1080 cmÀ1; MS (ESI): m/z 356 (M++Na); 1H NMR
(CDCl3, 600 MHz): d 1.35 (s, 3H), 1.58 (s, 3H), 1.61 (s, 3H), 1.91 (m,
1H), 2.58 (d, J = 12.1 Hz, 1H), 3.56 (dd, J = 13.2, 3.6 Hz, 1H), 4.01
(d, J = 13.2 Hz, 1H), 4.20 (d, J = 3.6 Hz, 1H), 4.20–4.24 (m, 2H), 4.70
(dd, J = 9.0, 3.6 Hz, 1H), 5.89 (d, J = 3.6 Hz, 1H), 6.97–7.28 (m, 5H).
13C NMR (CDCl3, 150 MHz): d 12.8 (CH3), 26.4 (CH3), 26.5 (CH2),
27.2 (CH3), 67.4 (CH), 67.6 (CH2), 78.8 (CH), 81.7 (CH), 85.4 (q),
88.4 (CH), 103.7 (CH), 112.0 (q), 115.6 (CH), 122.6 (CH), 128.8 (CH),
152.2 (q). Calcd for C18H23NO5: C, 64.85; H, 6.95; N, 4.20. Found: C,
64.93; H, 6.72; N, 4.46. Compound 5e: [a]D À238.3 (c 0.13, CHCl3);
E. Padmanabhan and Mr. K. Sarkar for NMR and mass
spectral analyses.
References and notes
1. Gothelf, K. V.; Jorgensen, K. A. Chem. Rev. 1998, 98, 863.
2. Osborn, H. M. I.; Gemmell, N.; Harwood, L. M. J. Chem. Soc.,
Perkin Trans. 1 2002, 2419.
3. Frederickson, M. Tetrahedron 1997, 53, 403.
4. Bhattacharjee, A.; Datta, S.; Chattopadhyay, P.; Ghoshal, N.;
Kundu, A. P.; Pal, A.; Mukhopadhyay, R.; Chowdhury, S.;
Bhattacharjya, A.; Patra, A. Tetrahedron 2003, 59, 4623. and
references cited therein.
5. Ghorai, S.; Mukhopadhyay, R.; Kundu, A. P.; Bhattacharjya, A.
Tetrahedron 2005, 61, 2999.
IR (neat): 2983, 2933, 1595, 1489, 1455, 1376, 1216, 1165, 1096 cmÀ1
;
MS (ESI): m/z 356 (M++Na); 1H NMR (CDCl3, 300 MHz): d 1.35 (s,
3H), 1.51 (s, 3H), 1.54 (s, 3H), 2.92 (m, 1H), 3.75 (d, J = 8.6 Hz, 1H),
3.83–3.93 (m, 4H), 4.21 (br s, 1H), 4.28 (d, J = 3.5 Hz, 1H), 5.88 (d,
J = 3.6 Hz, 1H), 7.00 (t, J = 7.2 Hz, 1H), 7.09 (d, J = 7.8 Hz, 2H),
7.31 (m, 2H). 13C NMR (CDCl3, 75 MHz): d 14.2 (CH3), 26.5 (CH3),
27.2 (CH3), 38.4 (CH), 60.5 (CH2), 63.7 (CH), 69.4 (CH2), 77.0 (CH),
79.7 (q), 87.4 (CH), 104.4 (CH), 112.2 (q), 114.9 (CH), 122.3 (CH),
129.1 (CH), aromatic quaternary C is not visible. HRMS: calcd for
C18H23NO5Na, m/z: 356.1474. Found: 356.1486. Compound 10: [a]D
+43.1 (c 0.31, CHCl3); MS (ESI): m/z 416 (M++Na); 1H NMR
(CDCl3, 300 MHz): d 1.09 (d, J = 7.2 Hz, 3H), 2.03 (s, 3H), 2.15 (s,
3H), 2.18 (s, 3H), 2.55 (m, 1H), 3.67 (dd, J = 13.5, 5.7 Hz, 1H), 3.85
(dd, J = 5.5, 1.9 Hz, 1H), 3.96 (m, 1H), 4.19–4.29 (m, 3H), 5.20 (m,
1H), 5.33 (m, 1H), 6.74 (m, 2H), 7.21 (m, 3H). 13C NMR (CDCl3,
75 MHz): d 15.6 (CH3), 20.8 (CH3), 20.9 (CH3), 21.0 (CH3), 33.3
(CH), 58.5 (CH), 62.3 (CH2), 69.6 (CH2), 72.6 (CH), 76.3 (CH), 77.2
(CH), 112.7 (CH), 117.8 (CH), 129.6 (CH), 147.3 (q), 169.7 (q), 170.2
(q), 170.7 (q). HRMS: calcd for C18H23NO5Na, m/z: C20H27NO7Na,
416.1685. Found: 416.1706. Compound 14: [a]D À153.4 (c 0.35,
CHCl3); IR (neat): 1731, 1640, 1596 cmÀ1; MS (EI): m/z 357 (M+); 1H
NMR(CDCl3, 300 MHz; mixture of diastereomers due to C–CH3): d
1.15–1.17 (m, 3H), 1.64 (s, 3H), 1.97–2.01 (m, 1H), 2.17–2.22 (m, 1H),
2.43 (m, 1H), 2.56–2.68 (m, 2H), 3.76 (dd, J = 13.8, 3.4 Hz, 1H), 3.98–
4.09 (m, 2H), 4.77–4.80 (m, 1H), 4.97–5.14 (m, 4H), 5.26 (d,
J = 17.2 Hz, 1H), 5.72–5.83 (m, 2H), 6.83–7.56 (m, 5H). 13C NMR
(CDCl3, 75 MHz): d 17.0 (CH3), 20.8 (CH3), 27.7 (CH3), 37.9 (CH2),
38.2 (CH2), 39.6 (CH), 39.7 (CH), 68.6 (CH2), 69.0 (CH), 69.1 (CH),
76.7 (CH), 76.9 (CH), 79.6 (CH), 79.7 (CH), 80.3 (q), 112.1 (CH2),
112.2 (CH2), 115.9 (CH), 117.3 (CH2), 118.0 (CH), 122.8 (CH), 129.1
(CH), 135.8 (CH), 137.9 (CH), 143.3 (CH), 143.4 (CH), 143.5 (CH),
152.5 (q), 175.6 (q), 175.7 (q). Compound 16: IR (neat): 1730, 1646,
1596 cmÀ1; MS (FAB): m/z 687 (M++H), 709 (M++Na); 1H NMR
(CDCl3, 300 MHz; as a mixture of E/Z and diastereomers due to
C–CH3): d 1.04–1.06 (m, 6H), 1.60–1.63 (m, 6H), 1.98–2.51 (m, 8H),
2.63 (dd, J = 11.9, 4.6 Hz, 2H), 3.76 (d, J = 13.8 Hz, 2H), 3.95–4.09
(m, 4H), 4.77 (m, 2H), 4.97–5.12 (m, 4H), 5.22–5.36 (m, 4H), 5.76–
5.85 (m, 2H), 6.82–7.55 (m, 10H).
6. Shing, T. K. M.; Zhong, Y.-L. Tetrahedron 2001, 57, 1573.
7. Shing, T. K. M.; Fung, W.-C.; Wong, C.-H. J. Chem. Soc., Chem.
Commun. 1994, 449.
8. Sharma, G. V. M.; Reddy, K. R.; Sankar, A. R.; Kunwar, A. C.
Tetrahedron Lett. 2001, 42, 8893.
9. Chatterjee, A.; Bhattacharya, P. K. J. Org. Chem. 2006, 71,
345.
10. General experimental procedure for nitrone cycloaddition. A solution of
the aldehyde 2 (1.5 mmol) and PhNHOH (2.2 mmol) in benzene
˚
(12 ml) containing 3 A molecular sieves (2.5 g) was heated at reflux for
5 h. The mixture was then filtered, and the residue obtained after
removal of the solvent from the filtrate was chromatographed over Si-
gel (100–200 mesh) to afford the products.
11. Physical data for new compounds. Compound 4c: [a]D À150.1 (c 0.31,
CHCl3); IR (neat): 2938, 1594, 1491, 1452, 1376, 1298, 1214, 1150,
1089, 1021, 856, 756, 698 cmÀ1; MS (ESI): m/z 418 (M++Na); 1H
NMR (CDCl3, 600 MHz): d 1.33 (s, 3H), 1.47 (s, 3H), 3.83 (d,
J = 13.2 Hz, 1H), 3.94 (dd, J = 13.2, 4.2 Hz, 1H), 4.20 (br s, 1H), 4.31
(m, 1H), 4.32 (s, 1H), 4.48 (d, J = 4.2 Hz, 1H), 4.52 (d, J = 3.6 Hz,
1H), 4.84 (d, J = 4.2 Hz, 1H), 6.03 (d, J = 3.6 Hz, 1H), 6.83 (t,
J = 7.2 Hz, 1H), 6.93 (d, J = 7.8 Hz, 2H), 7.11 (m, 7H). 13C NMR
(CDCl3, 150 MHz): d 26.2 (CH3), 26.6 (CH3), 47.2 (CH), 70.2 (CH),
72.7 (CH2), 77.4 (CH), 83.0 (CH), 83.1 (CH), 84.4 (CH), 104.7 (CH),
111.9 (q), 113.8 (CH), 121.0 (CH), 126.5 (CH), 127.8 (CH), 128.2
(CH), 128.7 (CH), 140.7 (q), 149.5 (q). HRMS: calcd for m/z:
C23H25NO5Na, 418.1630. Found: 418.1667; Compound 5c: mp 145–
146 °C; [a]D À160.1 (c 0.43, CHCl3); IR (KBr): 2907, 1596, 1490,
1380, 1265, 1215, 1163, 1085, 882, 758, 697 cmÀ1; MS (ESI): m/z 418
(M++Na); 1H NMR (CDCl3, 600 MHz): 1.31 (s, 3H), 1.43 (s, 3H),
2.98 (m, 1H), 3.77 (dd, J = 12.0, 10.2 Hz, 1H), 3.87 (d, J = 6.6 Hz,
1H), 4.04 (dd, J = 12.0, 6.0 Hz, 1H), 4.19 (d, J = 2.4 Hz, 1H), 4.23 (br
s, 1H), 4.58 (d, J = 3.6 Hz, 1H), 4.91 (d, J = 3.6 Hz, 1H), 5.88 (d,
J = 3.6 Hz, 1H), 7.13 (t, J = 7.2 Hz, 1H), 7.24–7.29 (m, 7H), 7.35 (d,
J = 7.8 Hz, 1H), 7.36 (d, J = 7.8 Hz, 1H). 13C NMR (CDCl3,
150 MHz): 26.1 (CH3), 26.7 (CH3), 46.6 (CH), 60.6 (CH), 64.8
(CH2), 73.0 (CH), 77.2 (CH), 81.0 (CH), 84.3 (CH), 104.3 (CH), 111.8