
%0 Journal Article
%A Massy-Westropp, R 
%A Price, M 
%T The Synthesis of 5-Oxo-2,5-dihydrofuran-2-ylideneacetic Acids
%J Australian Journal of Chemistry
%D 1980/02/01
%V 33
%N 2
%P 333-341
%K 
%R https://doi.org/10.1071/CH9800333
%U https://www.publish.csiro.au/paper/CH9800333 
%X The 5-oxo-2,5-dihydrofuran-2-ylideneacetic acids (2a), (3a), (9a), (10a), (11a), (12a) and (13a) have been synthesized by a procedure which allows the unambiguous assignment of the stereochemistry about the double bond in each isomer. The method, of general application, enables the acids to be prepared from the corresponding t-butyl esters with acid without isomerization about the double bond. The t-butyl esters are available from the Wittig reaction between anhydrides and t- butoxy-carbonylmethylenetriphenylphosphorane.Where mainly one isomer is produced in the Wittig reaction, isomerization to an easily separable mixture of the esters can be achieved. Aspects of the isomerization of enol-lactone esters (e.g. (2b)) are described. 
