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

Aromatic ortho ‐disulfone derivatives are readily accessible from diiodide precursors by Cu I ‐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 31 P‐ and 1 H‐NMR data of the chiral D 3 ‐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{{[(1 S ,4 R )‐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 1 H‐NMR in the temperature range of 110°, the corresponding free energy being 19.8 kcal⋅mol −1 .