Reaction #500683

Reaction equation

Potassium tert-butoxide

(methoxymethyl)-triphenylphosphonium chloride

methyl benzoylformate

magnesium sulphate

charcoal

→

E-methyl 3-methoxy-2-phenylpropenoate

Yield 50.3%

Solvents

water

ether

ether

Conditions

Workup

1. 1
   workup.WAITAfter 3 hours
2. 2
   Concentrationconcentrated under reduced pressure
3. 3
   Otherto give the crude product (36.39 g) as a yellow oil which
4. 4
   Otherpartially crystallised
5. 5
   OtherThis was flushed through silica gel
6. 6
   Othercarefully chromatographed

Procedure

Potassium tert-butoxide (9.52 g) was added in a single portion to a stirred suspension of (methoxymethyl)-triphenylphosphonium chloride (34.3 g) in dry ether (300 ml). After 45 minutes, the resulting red suspension was treated with a solution of methyl benzoylformate (8.20 g) in dry ether (100 ml) (colour lightens; exotherm). After 3 hours, the mixture was diluted with water, treated with magnesium sulphate and charcoal, then concentrated under reduced pressure to give the crude product (36.39 g) as a yellow oil which partially crystallised on standing. This was flushed through silica gel using dichloromethane, then carefully chromatographed using dichloromethane: petrol (2:1) to give E-methyl 3-methoxy-2-phenylpropenoate (4.83 g, 50% yield) as a pale yellow oil, eluted first, infrared (film): 1710, 1630 cm−1, 1H nmr (CDCl3): delta 7.55 (s, olefinic proton), and Z-methyl 3-methoxy-2-phenylpropenoate (3.43 g, 36% yield) as a pale yellow oil, eluted second, infrared (film): 1715, 1630 cm−1, 1H nmr (CDCl3): delta 3.76 (3H,s), 3.90 (3H,s), 6.65 (1H,s), 7.28 (5H,s) ppm.

Source