of synthetically useful reactions of 2-trimethylsilylmethyl-1,3-butadiene (7) are discussed. Reactions of 7 with acid chlorides, aldehydes, ketones and acetals activated by a Lewis acid give isoprenylated compounds, while 7 undergoes the Diels-Alderreaction with dienophiles. High regiospecificity of the reaction qualifies 7 for a versatile building block of terpene synthesis.