Silyl enolates that were generated from α-allyloxy esters afforded the corresponding [2,3]-Wittig rearrangement products in moderate to good yields on treatment with a catalytic amount of Lewis base such as tetrabutylammonium acetate or tetrabutylammonium 4-methoxybenzoate in DMF at room temperature.
Lewis base-catalyzed [2,3]-Wittig rearrangement of silyl enolates generated from α-allyloxy carbonyl compounds is described. The [2,3]-Wittig rearrangement of silyl enolates generated from α-allylo...
Stereochemical Prins cyclization: electronic versus steric effects on the synthesis of 2,4,6-trisubstituted tetrahydropyran rings
作者:Kok-Ping Chan、Ai-Hua Seow、Teck-Peng Loh
DOI:10.1016/j.tetlet.2006.11.023
日期:2007.1
A convenient approach towards the synthesis of both syn- and anti-2,4,6-chlorotetrahydropyrans has been developed. The electronic and steric influences on the stereochemistry of the Prins cyclized products were investigated based on the substituents of the homoallylic alcohol.