No abstract

The synthesis of acetoxy-endoperoxyacetal derivatives allowed the formation of functionalized 3,5-disubstituted-1,2dioxolanes through the formation of reactive peroxycarbenium species under Lewis acid mediation. The introduction of a neutral nucleophile such as allylsilanes, silanes, or silyl enol ethers was accomplished with moderate to good yields. The two studied Lewis acids, TiCl4 and SnCl4, gave contrasted results. The higher diastereoselectivity towards the trans diastereomer in experiments with TiCl4 as Lewis acid was explained by a faster degradation of the cis isomer product, conducting generally to lower yields. A rationalization of this result was supported by calculation. about towards one degradation pathway could rationalize why cis-1,2-dioxolanes decompose more easily under treatment with TiCl4.