402 1
J. Org. Chem. 1988, 53, 4021-4026 NMR (CDC1,) 6 0.99 (t, 3 H, J = 7.5 Hz),1.06 (d, 3 H,J = 6.3 Hz), 1.48-1.80 (m, 2 H),2.08 (m, 1 H,J = 6.3 Hz),2.66 (ddd, 1 H, J = 2.2,6.3,7.5 Hz),3.40 (d, 2 H,J = 6.3 Hz),3.63 (dd, 1 H, J = 2.2,6.3 Hz), 3.72 (s, 3 H),4.48,4.49 (AB system, 2 H, J = 12.2 Hz),7.25-7.40 (m, 5 H);'H NMR [CDCl, + Eu(hfc),] of 17 obtained from silyl ketene acetal 20,6 5.62 (296%,MeO, s), 5.68
+
(S4%, MeO, s); 'H NMR [CDCl, Eu(fod),] of 17 obtained from silyl ketene acetal 20,6 5.56 (296%, MeO, s), 5.45 (l%, MeO, s), 5.33 (13%, MeO, s); 'H NMR [CDCl, Eu(hfc),] of 17 obtained from silyl ketene acetal 19,6 6.37(?go%, MeO, s), 6.45 (
