Chlorinated Paracyclophanes: Composition Analysis and Direct Metal‐Free Alkylation with n ‐BuLi

A transition-metal-free alkylation of the dichloro[2.2]paracyclophane scaffold is reported, representing a significant advancement in the reactivity of this unique class of compounds. The pseudo-para isomer of dichloro[2.2]paracyclophane was isolated from a commercial mixture via crystallization, and its structure was assessed by detailed 1D and 2D NMR spectroscopy. The reaction of the purified isomer with butyllithium was investigated, and a systematic optimization revealed that reaction rate and selectivity were significantly improved by using a chelating agent and conducting the reaction in refluxing heptane. This refined protocol yielded the desired dialkylated product, establishing a new and more efficient synthetic pathway that opens the door to further exploration of this unprecedented reactivity.