Alternating cooligomerization of isoprene and propylene with vanadium catalyst

Alternating cooligomerization of isoprene with propylene has been investigated between −30 and 0°C, VO(acac)2–Et3Al–Et2AlCl being used as catalyst. In the presence of an excess of propylene, 2,4,7‐trimethyl‐1,4‐octadiene and 2,4‐dimethyl‐1,4‐nonadiene are selectively formed. The formation is explained by the alternating coordination of isoprene and propylene to the vanadium. When triphenylphosphine or pyridine is added to the catalyst, the cooligomerization is suppressed while the formation of the dimer and trimer of isoprene is high.