Pentadienyllithium (16) was regioselectively and efficiently transformed to 1‐trimethylsilyl‐2,4‐pentadiene (17) by reaction with chlorotrimethylsilane ( Scheme 5 ). Deprotonation of 17 and subsequent electrophilic attack furnished the regioisomeric products 12 and/or 13 in good yields ( Schemes 5 and 6 ). The utility of the reaction 18 → 12 for the convergent assembly of the 1‐silyl‐1,3‐butadiene unit with an olefinic dienophile is further illustrated by the smooth intramolecular Diels‐Alder reaction 19 → 20 .