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

HRID 2371277Notes

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-0be370b0c3d7499aa4230f4f3088e0fd
Source dataset: uspto-grants-2014_04
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08710236B2

Reaction notes

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