Methyl 4-Formylbenzoate → 4-(2-Benzyloxycarbonyl-2-bromo-vinyl)-benzoic acid methyl ester

HRID 1755172Notes

Reaction equation

[CH2:1]([O:8][C:9](=[O:18])[CH:10]([Br:17])P(OC)(OC)=O)[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.[Li+].C[Si]([N-][Si](C)(C)C)(C)C.[CH3:29][O:30][C:31](=[O:40])[C:32]1[CH:37]=[CH:36][C:35]([CH:38]=O)=[CH:34][CH:33]=1>C1COCC1>[CH3:29][O:30][C:31](=[O:40])[C:32]1[CH:37]=[CH:36][C:35]([CH:38]=[C:10]([C:9]([O:8][CH2:1][C:2]2[CH:3]=[CH:4][CH:5]=[CH:6][CH:7]=2)=[O:18])[Br:17])=[CH:34][CH:33]=1

Participants

Conditions

Temperature: 0 °C

Procedure

To a cooled (−78° C.) solution of bromo-(dimethoxy-phosphoryl)-acetic acid benzyl ester (500 mg, 1.5 mmol) in THF (10 mL) was added LHMDS (1.2 mL of a 1M solution in THF, 1.2 mmol). The reaction was warmed to 0° C. and stirred for 30 minutes, then recooled to −78° C. 4-Formyl-benzoic acid methyl ester (163 mg, 1.0 mmol) in THF (2 mL) was added dropwise, and the reaction was allowed to warm to room temperature and stirred for 18 hours. The reaction was evaporated to dryness by rotary evaporator and purified by column chromatography on silica gel eluting with 50% ethyl acetate in hexanes to yield 4-(2-Benzyloxycarbonyl-2-bromo-vinyl)-benzoic acid methyl ester (358 mg, 64%) as a mixture of E and Z isomers. 1H NMR (300 MHz, CDCl3): δ 8.33 (s, 1H), 8.05 (d, J=7.5 Hz, 1H), 7.88 (m, 2H), 7.4-7.2 (m, 7H), 5.33 (s, 1H), 5.16 (s, 2H), 3.93-3.91 (s, 3H). LC-MS m/z=376 [C18H15BrO4+H]+.

Workup

customrecooled to −78° C
temperatureto warm to room temperature
stirringstirred for 18 hours
customThe reaction was evaporated to dryness by rotary evaporator
custompurified by column chromatography on silica gel eluting with 50% ethyl acetate in hexanes

Sources & evidence

ORD record: ord-99f41fe1d255429a869264c4c4b6c0f4
Source dataset: uspto-grants-2015_10
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US09169201B2

Reaction notes

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