Sodium hydride → Ethyl 5-methyl-2-heptenoate

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

Sodium hydride (60% dispersion, 2.4 g, 65 mmol) was washed with hexane and suspended in dimethoxyethane 60 mL. While cooling in ice water bath triethyl phosphonoacetate was slowly added, calcd. 5 minutes. The reaction was stirred for 15 minutes at 0° C. and a solution of 3-methyl-1-pentanal 11 (6.5 g, 65 mmol) in imethoxyethane 20 mL was added. After refluxing overnight, it was concentrated, water and hexane were added, the organic phase was separated, and the aqueous portion discarded. The solution was washed twice with brine and dried on magnesium sulfate. The solvent was evaporated to give 12 (6.75 g, 61%). 1H-NMR (CDCl3) δ 6.89 (m, 1H, —CH2CH:CHCOOEt), 5.77 (d, 1H, —CH2CH:CHCOOEt), 4.16 (q, 2H, —COOCH2CH3), 2.15 and 1.98 (1H each and a multiplet, —CH2CH:CHCOOEt), 1.48 (m, 1H, C2H5(CH3)CHCH2), 1.30-1.10 (m), and 0.83.

Herkunft & Nachweise