Reactions of Trimethylsilyl Cyanide with α-Keto Esters: Selective Preparation of Either Methyl 4-(Trimethyl-silyl) oxy-4-cyano-2-oxopentanoate or Methyl 2-(Trimethylsilyl) Oxy-2-cyano-4-oxopentanoate

Abstract

The reaction of methy1 2,4-dioxopentanoate (3) with TMSCN in the presence of zinc iodide affords the TMS protected cyanohydrin enol ether 4, from which the TMS protected cyanohydrin 1 can be obtained. Treatment of 3 with TMSCN alone gives the isomeric cyanohydrin 2. Reactions of two other α-keto esters with TMSCN are shown to proceed without a catalyst.