Triflic Acid Mediated Dealkylative Lactonisation via NMR??Observable Alkyloxonium Intermediates

MP Muñoz, GC Lloyd??Jones

Index: Munoz, M. Paz; Lloyd-Jones, Guy C. European Journal of Organic Chemistry, 2009 , # 4 p. 516 - 524

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Citation Number: 10

Abstract

Abstract Trifluoromethanesulfonic acid (TfOH) efficiently induces the dealkylative cyclisation of pent-4-enoates to generate γ-lactones with high selectivity. For primary alkyl esters bearing an additional alkene, only monolactonisation occurs, even in the presence of excess TfOH. The kinetics of the reaction have been studied by 1 H NMR spectroscopy, which reveal that the TfOH acid undergoes a self-catalysed reaction with the pent-4- ...