A Four-Carbon Unit Reagent for the Regiospecific Synthesis of 2-Alkyl-Substituted 1,3-Butadienes

2-Alkyl-substituted butadienes are synthesized starting from a masked butadiene reagent, which allows the regiospecific synthesis of 2-alkylbutadienes by lithiation and subsequent reaction with alkyl halides or aliphatic aldehydes. The regioselectivity of the reaction with allylic halides and aliphatic and aromatic aldehydes is studied.