Synthesis of 3,5-Disubstituted 1,2-Dioxolanes through the 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.