Oxalic Acid → (Z)-3-(4-methoxyphenyl)-4-methyl-2-pentenal

Participants

Reaction Steps

The compounds were prepared according to the procedure described in Example 84 except that the reaction was worked up after 3 days. The following reagents were used: 1-(4-methoxyphenyl)-2-methylpropanone (17.8 g), diisopropylamine (32.2 mL), 1.6M 1-butyl lithium in hexane (143 mL), acetaldehyde N-tert-butylimine (14.75 mL), diethyl chlorophosphonate (16.6 mL) and tetrahydrofuran (200 mL). The work up, varied only in that the oxalic acid hydrolysis was run overnight at room temperature, furnished 21.3 g of crude product containing (E)- and (Z)-3-4-methoxyphenyl)-4-methyl-2-pentenal in the ratio of 2:3. An attempt to separate the crude by HPLC (ether-hexane; 3:17; multiple recycles) only resulted in mixtures of (E)-3-(4-methoxphenyl)-4-methyl-2-pentenal and (Z)-3-(4-methoxyphenyl)-4-methyl-2-pentenal with E/Z ratios that varied between 1:and 1:1.

Provenance & Evidence