WERKWIJZE TER BEREIDING VAN 1,1-DIHALOGEEN-4- -METHYL-1,3-PENTADIENEN.

摘要

1,1-Dihalo-4-methyl-1,3-pentadienes, key intermediates in the syntehsis of insecticidal dihalovinylcyclopropanecarboxylates, may be prepared in three steps beginning with the Friedel Crafts condensation of a vinylidene halide and an isobutyryl halide in the presence of a Lewis acid catalyst, followed by reduction of the 1,1-dihalo-4-methyl-1-penten-3-one produced thereby, and dehydration of the resulting 1,1-dihalo-3-hydroxy-4-methyl-1-pentene.