Asymmetric Synthesis of a (2<i>Z</i>,7<i>E</i>)-Cyclononadiene by an Intramolecular Cycloalkylation and Insight to Its Conformational Properties

Here, we report a novel synthesis of a monosubstituted, enantio- and diastereomerically enriched trans-cyclononadienol. The reaction consists of an enantioselective (−)-sparteine-mediated allylic lithiation of an achiral 7-chlorononadienyl carbamate and a subsequent stereospecific intramolecular allyllithium−allyl chloride coupling. The stereochemical course of the cyclization has been determined, and the high configurative stability of the chiral nine-membered carbocycle has been investigated by kinetic measurements and rationalized by computational calculations.