Sodium hydride → Benzyl 2-methoxycarbonyl-4-ethoxycarbonyl-pent-4-enoate
Reaction equation
[C:1]([O:8][CH2:9][C:10]1[CH:15]=[CH:14][CH:13]=[CH:12][CH:11]=1)(=[O:7])[CH2:2][C:3]([O:5][CH3:6])=[O:4].Br[CH2:17][C:18](=[CH2:24])[C:19]([O:21][CH2:22][CH3:23])=[O:20].[H-].[Na+]>C(#N)C>[CH3:6][O:5][C:3]([CH:2]([CH2:24][C:18]([C:19]([O:21][CH2:22][CH3:23])=[O:20])=[CH2:17])[C:1]([O:8][CH2:9][C:10]1[CH:11]=[CH:12][CH:13]=[CH:14][CH:15]=1)=[O:7])=[O:4]Participants
Procedure
The title compound was prepared stepwise. In the first step, benzyl methyl malonate was reacted with an equimolar amount of ethyl 2-(bromomethyl)propenoate and sodium hydride in acetonitrile to give the product, benzyl 2-methoxycarbonyl-4-ethoxycarbonyl-pent-4-enoate, in 43% yield [1H-NMR (CDCl3) δ(ppm): 1.28 (t, 3H); 2.92 (d, 2H); 3.60 (s, 3H); 3.83 (t, 1H); 4.20 (q, 2H); 5.17 (s, 2H); 5.58 (s,1H); 6.18 (s, 1H) and 7.32 (m, 5H)]. In the second step, to a cooled suspension of sodium hydride (0.30 g, 0.01 mol, 80% dispersion in oil) in acetonitrile (20 mL), was added benzyl 2-methoxycarbonyl-4-ethoxycarbonyl-pent-4-enoate (2.68 g, 0.0084 mol). The resulting mixture was allowed to stir for 10 minutes before a solution of t-butyl 2-(bromomethyl)propenoate (1.85 g) in acetonitrile (5 mL) was added and stirring continued at room temperature overnight under nitrogen. After work-up, the title product (21) was obtained in 72% yield as a colourless liquid. 1H-NMR (CDCl3) δ(ppm): 1.28 (t, 3H); 1.46 (s, 9H); 2.94 (s, 2H); 2.96 (s, 2H); 3.58 (s, 3H); 4.16 (q, 2H); 5.10 (s, 2H); 5.60 (s, 1H); 5.67 (s, 1H); 6.17 (s, 1H) and 7.32 (m, 5H).
Sources & evidence
- ORD record
- ord-2336336089bd4ea6b675a0ad9b75e3a2
- Source dataset
- uspto-grants-1998_11
- Patent number
- US05830966
Reaction notes
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