2,3-Dichlorobenzaldehyde → (S)-2,2,2-Trichloro-1-phenylethyl 2-(2,3-dichlorophenylmethylene)-3-oxobutanoate

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Reaction Steps

(S)-2,2,2-Trichloro-1-phenylethyl 3-oxobutanoate (8.6 g 27.5 mmoles) and 2,3-dichlorobenzaldehyde (4.82 g, 27.5 mmoles) in dry benzene (100 ml) were heated at reflux for 5 hours with hexanoic acid (25 drops) and piperidine (8 drops) in a Dean and Stark apparatus. The solvent was evaporated and the residue dissolved in ethyl acetate (200 ml), washed with saturated sodium bicarbonate, 2% aqueous sodium bisulphite solution and brine, dried (MgSO4) and the solvent removed in vacuo. The sub-title compound was obtained as a yellow oil. HPLC and nmr indicate 2:1 mixture of geometric isomers.

Provenance & Evidence