rhe dimerization of isoprene in the presence of bis (tripheny1phosphine) maleic anhydride palladium (0) occurs in exclusively tail-tail fashion to give 2, 7-dimethyl-1, 3, 7-octatriene(1). 2-Ethyl-1, 3-butadiene is dimerized similarly to give the corresponding 2, 7-diethyl derivative. Codimerization of isoprene and 1, 3-butadiene gives a mixture of codimers consisting of 7-methyl-1, 3, 7-octatriene (70%) and 2-rnethyl-l, 3, 7-octatriene(30%). 2, 3- ...