Propanal → 2-Methyl-4-(2,2,3-trimethylcyclopent-3-enyl)pent-2-enal

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Reaction Conditions

Reaction Steps

60.0 g (0.36 mol) of 2-(2,2,3-trimethylcyclopent-3-enyl)propionaldehyde, prepared from campholenic aldehyde as known per se, and 42.0 g (0.72 mol) of propanal was added successively during 15 min and 2 hours, respectively, to the sodium methylate solution prepared from 0.83 g of sodium and 200 ml of anhydrous methanol, at 10° C. The reaction mixture was stirred at 10° C. for 2 hours and at room temperature for the following 42 hours. After addition of 5 ml of acetic acid the solvent was evaporated in vacuo at the temperature maintained below 50° C. The residue was diluted with 500 ml of MTBE, washed with 2×200 ml of brine, dried (MgSO4), concentrated in vacuo and distilled at 76-95° C./0.1 Torr to give 28.1 g (38%) of 2-methyl-4-(2,2,3-trimethylcyclopent-3-enyl)pent-2-enal. An analytical sample was prepared by flash chromatography on silica gel (eluent: hexane/MTBE 12:1).

Provenance & Evidence