Scheme 10 Synthesis of methylene-tethered bisdioxanes from oligomethylene di(3-oxobutanoate)s nitrate, and iron(III) perchlorate, accelerated the oxidation of Mn(II) to Mn(III). The combination of manganese(II) acetate and a catalytic amount of manganese(III) acetate was the most effective for the cyclic peroxidation. Consequently, a 95% yield of the 1,2-dioxan-3-ol was achieved along with 3% 4,5-dihydrofuran in the reaction of 1,1-diphenylethene with ethyl 3-oxobutanoate using one equivalent of manganese(II) acetate containing a 0.1 equivalent of manganese(III) acetate.

When the reaction was applied to oligomethylene di(3-oxobutanoate)s, oligomethylene-tethered terminal bis(1,2-dioxan-3-ol)s were obtained in moderate yields [82](Scheme 10).

When a similar reaction of 1,1-diphenylethene with ethylene di(3-oxobu-tanoate) was stopped for 2.5 h, an intermediate monodioxane was obtained in 60% yield. The reaction that continued for 20 h resulted in the corresponding bis(1,2-dioxan-3-ol) in 52% yield together with the monodioxane (2%). Furthermore, the isolated monodioxane was allowed to react with the alkene under the same reaction conditions to produce the bis(1,2-dioxan-3-ol). Accordingly, it was suggested that the formation of the bis(1,2-dioxan-3-ol)s apparently occurred during the stepwise mechanism.

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