Abstract: Upon treatment in methanol at room temperature with methoxide ion methyl diarylmethanesulfinates, ArAr'CHS (0) OCH3 (l), and methyl 9-fluorenesulfinate (2) undergo elimination readily to afford the corresponding sulfines (3 and 4) in quantitative yield. Studies in CD30-/CD30D show that, surprisingly, elimination of 1 to give 3 is significantly faster than nucleophilic substitution by methoxide ion at the sulfinyl group (exchange of ...