V.; Reddy, D. K.; Suresh, V.; Chanti Babu, D.; Venkateswarlu, Y. Tetrahedron
Lett. 2010, 51, 946–948; (d) Chandra Rao, D.; Reddy, D. K.; Shekhar, V.;
Venkateswarlu, Y. Tetrahedron Lett. 2013, 54, 828–829.
5. (a) Brown, S. P.; Brochu, M. P.; Sinz, C. J.; MacMillan, D. W. C. J. Am. Chem.
Soc. 2003, 125, 10808–10809; (b) Yadav, J. S.; Reddy, U. V. S.; Reddy, B. V. S.
Tetrahedron Lett. 2009, 50, 5984–5986.
6. (a) Zhong, G.; Yu, Y. Org. Lett. 2004, 6, 1637–1639; (b) Mangion, I. K.;
MacMillan, D. W. C. J. Am. Chem. Soc. 2005, 127, 3967–3974; (c) Ramulu, U.;
Ramesh, D.; Rajaram, S.; Reddy, S. P.; Venkatesham, K.; Venkateswarlu, Y.
Tetrahedron: Asymmetry 2012, 23, 117–123.
7. Matovic, N. J.; Hayes, P. Y.; Penman, K.; Lehmann, R. P.; De voss, J. J. J. Org.
Chem. 2011, 76, 4467-4481.
8. (a) Reddy, D. K.; Shekhar, V.; Reddy, T. S.; Reddy, S. P.; Venkateswarlu, Y.
Tetrahedron: Asymmetry 2009, 20, 2315–2319; (b) Ohtani, I.; Kusumi, J.;
Kashman, Y.; Kakisawa, H. J. Am. Chem. Soc. 1991, 113, 4092–4096; (c)
Yoshido, W. Y.; Bryan, P. J.; Baker, B. J.; McClintock, J. B. J. Org. Chem. 1995,
60, 780–782.
9. Spectral data for selected compounds:
Compound 3: [α]D25 = +5 (c 0.4, CHCl3); IR (neat): 3492, 2938, 2837, 1713, 1656,
1515, 1462, 1264, 1238, 1158, 1030 and 767 cm-1; 1H NMR (300 MHz, CDCl3): δ =
7.0 (dd, J = 15.6, 4.5 Hz, 1 H), 6.85-6.71 (m, 3 H), 6.05 (d, J = 15.6 Hz, 1 H), 4.55-
4.44 (m, 1 H), 4.20 (q, J = 7.1 Hz, 2 H), 3.86 (s, 6 H), 2.91 (dd, J = 13.6, 4.9 Hz, 1
13
H), 2.72 (dd, J = 13.6, 8.1 Hz, 1 H), 1.28 (t, J = 7.1 Hz, 3 H); C NMR (75 MHz,
CDCl3): δ = 166.4, 148.9, 148.8, 147.8, 129.1, 121.4, 120.4, 112.5, 111.2, 71.6, 60.3,
55.8, 55.7, 42.7, 14.1; ESIMS: [M + Na]+ 303; Compound 4: [α]D25 = +0.6 (c 1.0,
CHCl3); IR (neat): 2954, 2932, 2856, 1719, 1657, 1515, 1465, 1262, 1159, 1115,
1032, 833 and 774 cm-1; 1H NMR (300 MHz, CDCl3): δ = 6.96 (dd, J = 15.1, 4.5 Hz,
1 H), 6.81-6.68 (m, 3 H), 5.96 (d, J = 15.1 Hz, 1 H), 4.46-4.37 (m, 1 H), 4.18 (q, J =
7.5 Hz, 2 H), 3.86 (s, 6 H), 2.83-2.65 (m, 2 H), 1.28 (t, J = 7.5 Hz, 3 H), 0.86 (s, 9 H),
13
-0.07 (s, 3 H), -0.20 (s, 3 H); C NMR (75 MHz, CDCl3): δ = 166.5, 150.2, 148.5,
147.7, 130.1, 121.8, 120.0, 113.2, 111.1, 73.1, 60.2, 55.9, 55.7, 43.8, 25.7, 18.1, 14.2,