Synthesis, Enantiomeric Conformations, and Stereodynamics of Aromatic ortho‐Substituted Disulfones

Abstract

AbstractAromatic ortho‐disulfone derivatives are readily accessible from diiodide precursors by CuI‐mediated reaction with sodium sulfinate salts (DMF, 110°). The sulfonyl substituents adopt in solution and in the solid state two enantiomeric conformations (λ and δ) as evidenced by 31P‐ and 1H‐NMR data of the chiral D3‐symmetric tris{4,5‐bis[(4‐methylphenyl)sulfonyl]benzene‐1,2‐diolato(2−)‐κO,κO′}phosphate(v) anion (3a) and 1,2‐bis(camphor‐10‐sulfonyl)‐4,5‐dimethoxybenzene ((=1,2‐bis{{[(1S,4R)‐7,7‐dimethyl‐2‐oxobicyclo[2.2.1]hept‐1‐yl]methyl}sulfonyl}‐4,5‐dimethoxybenzene; 6c). X‐Ray structure analysis of 1,2‐dimethoxy‐4,5‐bis(methylsulfonyl)benzene (6a) and 1,2‐dimethoxy‐4,5‐bis(4‐methylphenyl)sulfonyl]benzene (6b) confirmed in the solid state the preferred chiral orientation of the sulfonyl groups. Dynamic conformational isomerism was detected for 6c in its 1H‐NMR in the temperature range of 110°, the corresponding free energy being 19.8 kcal⋅mol−1.