反应详情

To a solution of 3-ethyl-4-hydroxy-5-methyl-benzonitrile (2.89 g, 17.9 mmol) in THF (80 mL), (R)-(2,2-dimethyl-[1,3]dioxolan-4-yl)methanol (2.84 g, 21.5 mmol) followed by triphenylphosphine (5.81 g, 21.5 mmol) is added. The mixture is cooled with an ice-bath before DEAD (9.36 g, 21.5 mmol) is added dropwise. The mixture is stirred at rt for 1 h, the solvent is removed in vacuo and the residue is purified by CC on silica gel eluting with heptane:EA 85:15 to give (R)-4-(2,2-dimethyl-[1,3]dioxolan-4-ylmethoxy)-3-ethyl-5-methyl-benzonitrile (4.45 g) as a pale yellow oil; LC-MS**: tR=0.75 min, [M+1]+=not detected; 1H NMR (CDCl3): δ1.25 (t, J=7.5 Hz, 3H), 1.44 (s, 3H), 1.49 (s, 3H), 2.34 (s, 3H), 2.65-2.77 (m, 2H), 3.80-3.90 (m, 2H), 3.94-4.00 (m, 1H), 4.21 (t, J=7.3 Hz, 1H), 4.52 (quint, J=5.8 Hz, 1H), 7.35 (s, 1H), 7.38 (s, 1H).

1. additionis added
2. additionis added dropwise
3. customthe solvent is removed in vacuo
4. customthe residue is purified by CC on silica gel eluting with heptane:EA 85:15