22430-47-3

bp 46–49°C/15 mmHg; n20 D 1.4679.

(1E,3E)-1,4-Bis(trimethylsilyl)-1,3- butadiene is a building block for the stereodefined construction of conjugated polyenyl chains.
Bromine addition leads to a tetrabromo derivative which can be bromodesilylated to (1Z,3Z)-1,4- dibromobutadiene (eq 3).

coupling of the Grignard reagent derived from (E)-2-(trimethylsilyl)-1-bromoethylene with the same bromo derivative leads to the silyldiene in 51% yield;a higher yield (62%) is obtained by reaction of bis(trimethylsilyl)- methyllithium with (E)-3-(trimethylsilyl)-2-propenal.Other procedures involve the Pd0-catalyzed demercuration of bis[(E)- (2-trimethylsilylvinyl)]mercury, prepared from (E)-2-(trimethylsilyl)- 1-lithioethylene and HgCl2 (77% yield),or the reaction of (E)-1,4-bis(trimethylsilyl)-2-butene with n-BuLi and TMEDA and subsequent oxidation with HgCl2 of the isolated bis-lithiated species, stabilized by complexation with TMEDA (57% yield).