OXIDATION OF SULFIDES BY OPEROXY-4,4,5,5-TETRAMETHYL-3-PHENYL-1,2-DIOXOLANE - EFFECT OF SOLVENT AND SULFIDE SUBSTITUENT

The reaction of peroxy-4,4,5,5-tetramethyl-3-phenyl-1,2-dioxolane, 1, with a series of sulfides (2a = thioanisole, 2b = ethyl phenyl sulfide , 2c = 2-chloroethyl phenyl sulfide, and 2d = 2-chloroethyl methyl sul fide) at 34 degrees C in various solvents yielded the corresponding su lfoxides and 3-hydroxy-1,2-dioxolane 3 in quantitative yields. The oxi dations showed excellent second-order kinetic behavior overall. In CDC l3, the reactivity order tvas 2d > 2b > 2a > 2c. For 2a, the relative rate in various solvents was CDCl3 (17); CD3OD (7); C6D6 (similar to 3 ); CD3CN (1); CD3C(O)CD3 (similar to 0.3). Addition of similar to 1 eq uivalent of acetic acid to reactions of 1 and 2a in CDCl3 and C6D6 res ulted in small increases in the values of k(2). The results are consis tent with an electrophilic oxygen-atom transfer mechanism similar to t har proposed for oxidations by alpha-azohydroperoxides. Since the prec ursor to 1, 3-hydroxy-1,2-dioxolane 3, is regenerated during the oxida tion, the system has the potential to be developed as a cyclic process . (C) 1998 John Wiley & Sons, Inc.