Triethyl phosphonoacetate → Ethyl 4-(3-chlorophenyl)-3-methylbut-2-enoate

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

At 0° C., a suspension of 60% w/w NaH/mineral oil (7.13 g, 0.176 mol) in THF (250 mL) was treated dropwise with a solution of ethyl 2-(diethoxyphosphoryl)acetate (39.5 g, 0.176 mol) in THF (72 mL) over a 30 min period. The reaction was stirred for another 30 minutes, and a solution of 1-(3-chlorophenyl)propan-2-one (19.7 g, 0.117 mol) in THF (108 mL) was added dropwise over 1 h (reaction was kept at 0° C. during addition). The reaction was allowed to warm to 23° C. overnight and quenched with saturated aqueous NH4Cl (250 mL). After 2 h, the mixture was diluted with water (250 mL) and hexane (100 mL). The organic phase was collected. The aqueous layer was extracted with EtOAc (2×150 mL). Combined organic phases were dried (MgSO4), filtered, and concentrated, giving crude ethyl 4-(3-chlorophenyl)-3-methylbut-2-enoate as a mixture of E and Z isomers. The residue was carried onward without further purification. (˜25 grams). The 1H NMR reported below is from a crude mixture containing both the E and Z isomer. 1H NMR (400 MHz, CDCl3) δ 7.24-7.22 (m, 2H), 7.16 (s, 1H), 7.06-7.04 (m, 1H); 5.67 (s, 1H); 4.18-4.13 (dd, 2H); 3.40 (s, 2H), 2.11 (s, 3H), 1.30-1.26 (t, 3H).

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