Synthesis of 3,5-Disubstituted 1,2-Dioxolanes throughthe Use of Acetoxy Peroxyacetals

The synthesis of acetoxyendoperoxyacetal derivatives allowed the formation of functionalized 3,5-disubstituted 1,2-dioxolanes through the formation of reactive peroxycarbenium species under Lewis acid mediation. The introduction of a neutral nucleophile such as allylsilane, silane, or silyl enol ether was accomplished with moderate to good yields. The two studied Lewis acids, TiCl4 and SnCl4, gave contrasting results. The higher diastereoselectivity toward the trans diastereomer in experiments with TiCl4 as Lewis acid was explained by a faster degradation of the cis isomer product, leading generally to lower yields. A rationalization of this result was supported by calculations.