Methyl 4-Formylbenzoate → Methyl 4-(2-methoxyethenyl)benzoate

To a suspension of (methoxymethyl)triphenylphosphonium chloride (6.366 g, 18.5 mmol) in dry tetrahydrofuran (50 ml) under argon atmosphere at −78° C. slowly (ca. for 5 minutes) a 2.46 N solution of potassium tert-butoxide in tetrahydrofuran (8.2 ml, 20.2 mmol) was added and the reaction mixture was stirred at this temperature for 1 hour. A solution of methyl 4-formylbenzoate (E8) (2.531 g, 15.4 mmol) in tetrahydrofuran (10 ml) was added to the reaction mixture and the resultant suspension was stirred at −78° C. for 30 minutes. The cooling bath was removed and the reaction was stirred for 30 minutes allowing to warm up to room temperature. The reaction mixture was partitioned between benzene (150 ml) and water (150 ml), and the organic layer was washed successively with water (150 ml), brine (50 ml), and dried (Na2SO4). The solvent was evaporated and the residue was chromatographed on silicagel (100 g) with toluene-triethylamine (100:0.25) as eluent to give the title compound (2.696 g, 91%) as a mixture of E and Z isomers (ca. 95:5). (E)-(E9): 1H NMR (CDCl3, HMDSO) δ: 3.67 (3H, s); 3.86 (3H, s); 5.81 (1H, d, J=13.5 Hz); 7.14 (1H, d, J=13.5 Hz); 7.25 (2H, d, J=8.5 Hz); 7.89 (2H, d, J=8.5 Hz). A small additional singlet at 3.80 ppm and 2 doublets at 5.23 (d, J=7.6 Hz); 6.22 ppm (d, J=7.6 Hz) in the 1H NMR spectrum of E9 was attributed to minor amounts (ca. 5%) of (Z)-(E9) isomer present in the product.

1. additionwas added
2. customThe cooling bath was removed
3. stirringthe reaction was stirred for 30 minutes
4. customThe reaction mixture was partitioned between benzene (150 ml) and water (150 ml)
5. washthe organic layer was washed successively with water (150 ml), brine (50 ml)
6. dry with materialdried (Na2SO4)
7. customThe solvent was evaporated
8. customthe residue was chromatographed on silicagel (100 g) with toluene-triethylamine (100:0.25) as eluent

ORD record

ord-1afc5f3b1b3a46bab38f4df62c96110b

Source dataset

uspto-grants-2008_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07465719B2