Reaktionsschritte
Pantothenic acid (7) (4.6 g, 2.24×10−2 mols) was dissolved in dry DCM (30 mL). Camphor sulfonic acid (0.52 g, 2.24×10−3 mols) and p-anisaldehyde-dimethoxy-acetal (3.82 mL, 2.24×10−2 mols) were added to the reaction mixture. The reaction was stirred overnight at room temperature with a drying tube. The crude reaction product was concentrated and purified silica gel chromatography (6:1 hexane:EtOAC-EtOAc) to yield a white solid (8A1) (3.8 g, 51% yield). mp=135-136° C. 1HNMR (400 MHz, DMSO) 0.93 (s, 3H), 0.99 (s, 3H), 2.38 (t, 2H, J=6.8 Hz), 3.25 (m, 1H), 3.34 (m, 1H), 3.5.9 (d, 1H, J=10.8 Hz), 3.62 (d, H, J=10.8 Hz), 3.74 (s, 3H), 4.07 (s, 1H), 5.50 (s, 1H), 6.91 (d, 2H, J=8.8 Hz), 7.41 (d, 2H, J=8.8 Hz). 13C-NMR (400 Mz, DMSO) 19.7, 22.2, 33.2, 34.4, 34.9, 55.8, 78.0, 83.8, 101.1, 114.0, 128.4, 131.1, 160.3, 168.9, 173.8. IR (NaCl, thin film), 3420, 2959, 1729, 1654, 1617, 1540, 1520, 1251, 1105 cm−1. MS (ESI) [M+Na]+360.1. HRMS (FAB) (m/z): [M+H]+ calcd for C17H23O6N, 338.1598, found 338.1594.
