The catalysis of a reaction of 4,4-dicarbomethoxy-1-cyclopropyl-1,6-heptadiene and HSiMe2OSiPh2t-Bu by a 1:1 mixture of (phen)Pd(Me)Cl (phen = 1, 10-phenanthroline) and NaBAr4 [Ar = 3, 5-C6H3(CF3)2] in Ch2Cl2 at 0° C for 12 h was presented. The (E)-trans-3-(1-butenyl)-4-(3-tertbutyl-1,1-dimethyl-3,3-diphenyldisiloxymet hyl)-1,1-dicarbomethoxycyclopentane in 93% isolated yield as a 25:1 mixture of isomers was formed by the catalysis. The generation of active cationic palladium catalyst in situ from mixtures of (phen)Pd(Me)Cl and NaBAr4[Ar= 3,5-C6H3(CF3)2] was also observed.