alpha-Acidities of conformationally constrained sulfides, sulfoxides and sulfones

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Knowledge of structural properties and stabilities of chemical compounds is essential for the understanding of the compound´s reactivities and would allow for the development of new synthetic methods. The reactivity of chemical compounds is significantly ruled (inter alia) by their acidities. We will determine the acidities of sulfides, sulfoxides, and sulfones by measurement and by quantum chemical calculations and will reveal the reasons for these acidities. By utilization of conformationally constrained substrates we will be able to determine, which influence comes from an orientation of the functional groups relative to the respective acidic protons. This knowledge is especially relevant for the development of stereoselective reactions. The synthesis of these conformationally constrained compounds is part of this project; we plan to focus on 1,3-dithiane and 2-thiaadamantane derivatives. We will optimize and use an existing method for the measurement of the acidities based on a titration in the presence of UV indicators. The acidities will be calculated using DFT methods; they will be rationalized with natural bond orbital (NBO) and isodesmic calculations.