5-Methyl-2-hexanone → 3-Chloro-2-isobutyl-but-2-enal

Participants

Reaction Conditions

Reaction Steps

Phosphorusoxychloride (53.7 g, 350 mmol) is slowly added to DMF (60 mL) stirred at 5° C. Upon complete addition, the clear solution is stirred for further 30 min at 5° C. before 5-methyl-2-hexanone (20 g, 175 mmol) is added dropwise. The yellow solution is stirred for 30 min at 0° C., then for 90 min at rt. The mixture becomes warm (40° C.) and a thick suspension forms. The mixture is cooled to 25° C. and stirring is continued for 1 h before it is poured into an aq. solution of NaOAc (80 g)/ice mixture. The mixture is extracted twice with diethyl ether. The organic extracts are washed with water, combined, dried over MgSO4, filtered and evaporated to give crude 3-chloro-2-isobutyl-but-2-enal (35.4 g) as a yellow oil, LC-MS: tR=0.97 min.

Provenance & Evidence