2-Trimethylsilylethyl-1,3-butadiene, readily prepared by the cross-coupling reaction of the Grignard reagent of 3-bromo-3-butenyltrimethylsilane with vinyl bromide catalyzed by a nickel-phosphine complex, works as a synthetic equivalent to 3-methylene-1,4-pentadiene (parent [3ldendralene) by the consecutive Diels-Alder reactions. Much attention has been recently directed to consecutive cycloaddition which may be one of the most useful and convenient route to linear and nonlinear polycyclic hydrocarbons,2 important biologically active materials. 3 Recently we have reported that 2-aminomethyl-3-silylmethyl-1,3-butadiene reacts with two dienophiles aia consecutive cycloaddition-1,4-eliminationcycloaddition, giving octahydronaphthalenes and related linear polycycles of the structures in which 2,3,6,7-substitution pattern is substantially involved, and that this works as synthetic equivalents of 2,2'-biallyl diradical and zwitterion. 4 In an extension of the study on the synthetic application of organosilicon compounds to organic synthesis,5 we now report that 2trimethylsilylethyl-1,3-butadiene (11, the title compound, is a synthetic equivalent to parent cross-conjugated hexatriene (2, [3ldendralene), unstable and otherwise inaccessible,6 by the consecutive cycloaddition-1,2-elimination-cycloaddition (Scheme 1). This reagent works as an active l+diene, affording the corresponding octahydronaphthalenes (5) of the structures, in which the eventual "elbow bend" is implicit in the 3,4,6,7-substitution pattern.