Ester enolate Claisen rearrangement using a polymer-supported silyl triflate

Article abstract of DOI:10.1016/S0040-4039(99)00441-4

Polystyrene-diethylsilane resin (PS-DES) was treated with triflic acid to form a highly reactive polymer silyl triflate. The silyl triflate reacted with enolizable allylic esters in the presence of Et,N to afford resin-bound silyl ketene acetals, which undergo Ireland-Claisen rearrangement at elevated temperature to provide polymer silyl esters. Transesterification of the polymeric silyl esters with 5% H₂SO₄ in 1:1 MeOH/ClCH₂CH₂Cl (DCE) afforded methyl ester products.