Sodium bis(trimethylsilyl)amide → Cyclopentyl-2-(3,4-dichloro-phenyl)-acrylic acid methyl ester

Participants

Reaction Conditions

Reaction Steps

A suspension of cyclopentylmethyl triphenylphosphonium iodide (prepared in Example 3, 3.95 g, 8.37 mmol) in dry tetrahydrofuran (10 mL) was cooled to 0° C. and then treated dropwise with a 1.0M solution of sodium bis(trimethylsilyl)amide (8.4 mL, 8.37 mmol). The bright orange reaction mixture was stirred at 0° C. for 45 min. The reaction mixture was then treated with a solution of (3,4-dichloro-phenyl)-oxo-acetic acid methyl ester (1.30 g, 5.58 mmol) in tetrahydrofuran (4 mL). The resulting reaction mixture was allowed to warm to 25° C. where it was stirred for 64 h. The reaction mixture was then concentrated in vacuo to remove tetrahydrofuran. The residue was diluted with water (150 mL) and then extracted with diethyl ether (1×200 mL). The organic layer was dried over sodium sulfate, filtered, and concentrated in vacuo. Flash chromatography (Merck Silica gel 60, 70-230 mesh, 19/1 hexanes/ethyl acetate) afforded the 3 cyclopentyl-2-(3,4-dichloro-phenyl)-acrylic acid methyl ester (821.1 mg, 49%) as a yellow oil consisting of a 4.5:1 mixture of (E):(Z) isomers. The isomeric mixture was used without further separation and characterization.

Provenance & Evidence