(5AS,7S)-7-ISOPROPENYL-3-METHYL-6,7,8,9-TETRAHYDRO-5AH-PYRANO[4,3-B]CHROMEN-1-ONE synthesis

Yield:194937-75-2 78%

Reaction Conditions:

with L-proline in ethyl acetate at 70; for 12 h;

Steps:

2

From 1.000 g (7.93 mmol) of pyrone 20 and 1.191 g (7.93 mmol) of S-perilaldehyde (22), 1.596 g (78% yield) of 24 was obtained after column chromatographic separation: yellow solid, mp 140-141° C.; [α]²²_D=+31.9° (c 0.75, CHCl₃); ¹H NMR δ 6.1 (s, 1H, C10H), 5.72 (s, 1H, C4H), 5.1 (dd, J=11 Hz, 5 Hz, 1H, C5aH), 4.75 (m, 1H, CH), 4.73 (m, 1H, CH), 2.48 (ddd, J=14 Hz, 4 Hz, 2.4 Hz, 1H), 2.22-2.02 (series of m, 3H), 2.19 (s 3H, C4-Me), 1.88-1.72 (series of m, 2H), 1.74 (s, 3H, MeC), 1.31 (ddd, J=25 Hz, 12.8 Hz, 4 Hz, 1H); ¹³C NMR δ 163.4 (s, CO), 162.6 (s, C3), 161.7 (s, C4a), 147.9 (s, C10a), 132.3 (s, C), 109.8 (d, C10), 109.6 (t, CH₂), 99.9 (d, C4), 97.5 (s, C9a), 79.4 (s, C5a), 43.6 (d, C7), 40.0 (t), 32.5 (t), 32.1 (t), 20.9 (q, Me), 20.3 (q, Me); MS FAB, m/z 259 (M+1, 70%), 258, 257, 215, 189, 139 (100). Anal. Calcd for C₁₆H₁₈O₃: C, 74.4; H, 7.02. Found: C, 74.17; H, 7.33.

References:

US6916824,2005,B1 Location in patent:Page/Page column 29