processes and intermediates for the manufacture of 2.13 octadecadienylacetat and its use

摘要

Process for the preparation of a mixture of E2,Z13-octadecadienyl acetate Ia and Z2,Z13-octadecadienyl acetate 1b IMAGE characterised in that Z11-hexadecenal II IMAGE is reacted in a manner known per se in the presence of a base with a phosphonium salt of the formula III (C6H5)3P+CH2CH(OR1)OR2X- III in which R1 and R2 represent alkyl having 1 to 8 C atoms or together represent -CH2CH2- or -CH2CH2CH2-, it being possible for one to three hydrogen atoms in these chains to be replaced by C1-C3 alkyl groups, and X represents halogen, to give E2,Z13-octadecadienyl acetal IVa or Z2,Z13-octadecadienyl acetal IVb IMAGE or, with simultaneous cleavage of the acetal, to give E2,Z13-octadecadienal Va or Z2,Z13-octadecadienal Vb IMAGE IVa and IVb, or Va and Vb, are subsequently reduced to give the corresponding alcohol VIa or VIb, respectively, IMAGE and VIa and VIb are acetylated in a manner known per se.