The results of kinetic, deuterium-labeling, and low-temperature NMR studies have established a mechanism for the palladium-catalyzed cyclization/hydrosilylation of dimethyl diallylmalonate (1) with triethylsilane involving rapid, irreversible conversion of the palladium silyl complex [(phen)Pd(SiEt3)(NCAr)](+) [BAr4](-) [Ar = 3,5-C6H3(CF3)(2)] (4b) and 1 to the palladium 5-hexenyl chelate complex {(phen)Pd[eta(1), eta(2)-CH(CH2SiEt3)CH2C(CO2Me)(2)CH2CH=CH2]}(+) [BAr4](-) (5), followed by intramolecular carbometalation of 5 to form the palladium cyclopentylmethyl complex trans-{(phen)Pd[CH2CHCH2C(CO2Me)(2)CH2CHCH2SiEt3]-(NCAr)}(+) [BAr4](-) (6), and associative silylation of 6 to release 3 and regenerate 4b.