Enantioselective alkynylation of cyclopentanone: Synthesis, dimerization, and cross-coupling transformations of ۱-ethynylcyclopentan-۱-ol

In the present investigation, the preparation of ۱-ethynylcyclopentan-۱-ol was carried out via the enantioselective alkynylation of cyclopentanone using a Zn(OTf)₂/TBAF·۳H₂O complex catalytic system. Тhe process was carried out in acetonitrile (MeCN) medium for ۱۲۰ minutes at –۱۰ °C. The molar ratio of acetylene to cyclopentanone was adjusted to ۲:۱, while the combined loading of the catalytic system Zn(OTf)۲/TBAF·۳H۲O was maintained at ۰.۰۵ mol with respect to the starting materials. Furthermore, its subsequent oxidative homolytic dimerization and Sonogashira-type C–C cross-coupling reaction with benzyl chloride were explored. A comprehensive study was performed on various parameters affecting the formation process and the efficiency of acetylene alcohol derivatives, such as temperature regime, reaction time, catalytic composition and solvent polarity, stoichiometric ratios of reagents and substrates, as well as the identity and proportion of transient intermediates and side-products. Based on the acquired experimental data, the optimal conditions for the nucleophilic addition–coupling pathway were established, and the plausible reaction mechanisms were proposed. The obtained compounds were thoroughly characterized, and their equilibrium constants, molecular structures, purity levels, and chemical composition were verified using modern physicochemical analysis techniques.

کلیدواژه ها:

acetylene alcohol ، dimerization ، сross-coupling reaction ، Reaction mechanism ، Product Yield