Tributylphosphine Catalyzed O -Vinylation of 3-Hydroxy-2-methyl-4 H -pyran-4-one

Abstract

Protonation of the highly reactive 1:1 intermediates produced in the reaction between tributylphosphine and dimethyl acetylenedicarboxylate by 3-hydroxy-2-methyl-4 H -pyran-4-one leads to vinyltributylphosphonium salts, which undergo an addition-elimination reaction in CH 2 Cl 2 at room temperature to produce dimethyl 2-[(2-methyl-4-oxo-4 H -pyran-3-yl)oxy]-2-butenedioate (1:1 mixtures of E and Z isomers) in fairly good yields.

Keywords:

• Acetylenic Ester
• Catalyst
• 3-hydroxy-2-methyl-4 H -pyran-4-one
• Tributylphosphine
• Vinyltributylphosphonium Salt