Dependence of Stereoelectronic and Charge Effects on pKa Values of 1, 3‐Dithiane‐Derived Sulfides, Sulfoxides, and Sulfones: An Experimental and Computational Investigation. Issue 5 (23rd December 2014)

• Record Type: Journal Article
• Authors: Süveges, Bastian D.; Podlech, Joachim
• Is Part Of: European journal of organic chemistry. Issue 5(2015)
• Page Start: 987
• Page End: 994
• Publication Date: 2014-12-23
• Subjects: Stereoelectronic effects -- Sulfur heterocycles -- Sulfoxides -- Acidity -- UV/Vis spectroscopy; Chemistry, Organic -- Periodicals; Organic compounds -- Synthesis -- Periodicals; Bioorganic chemistry -- Periodicals; Chemistry, Physical organic -- Periodicals; 547
• DOI: 10.1002/ejoc.201403409
• Languages: English
• ISSNs: 1434-193X

Abstract

Abstract: The p K a values of conformationally fixed 1, 3‐dithianes were investigated with experimental and theoretical methods to gain an insight into the influence of the relative orientation of the acidic proton and the stabilising S=O or S–C bonds. Experimental values were determined with a modification of the spectrophotometric method using overlapping indicators developed by Bordwell; theoretical values were obtained with the proton exchange methods using DFT calculations. It turned out that stereoelectronic stabilisation is important for sulfides and sulfoxides, whereas charge effects become dominant in sulfones. Deprotonation of the equatorial proton is favoured for most of the compounds except for the equatorial/axial bis‐sulfoxide. Abstract : Whereas the α‐acidity of sulfoxides depends on the relative orientation of the acidic C–H and S=O bonds, this effect is significantly less pronounced in sulfones.