Study of reactions leading to sulfine formation. 5. Methoxide-catalyzed decomposition of diarylmethyl(arylsulfonyl)methyl sulfoxides: a sulfine-forming elimination on the E1cBrev/(E1cB)irrev borderline

Abstract

In 7:3 CH 3 OH-DMSO (v/v) in the presence of methoxide ion, diarylmethyl (arylsulfonyl) methyl sulfoxides (Ar 2 CHS(O)CH 2 SO 2 Ar') 4, undergo elimination remarkably easily to afford the diarylsulfine and the aryl methyl sulfone. Comparison of the rate of cleavage of 4 (κ elim ) and the rate of disappearance of the 1 H NMR signal (κ CHSO ) for the Ar 2 CHS(O) proton in CD 3 OD(DMSO shows that the mechanism for the elimination is on the (ElcB) REV /(ElcB) irrev borderline, (κ CHSO /κ elim ) ranging from 1.2 to 5.2, depending on the nature of the Ar and Ar' groups in 4