Use of Tetraethyl Dimethylaminomethylenediphosphonate in the Synthesis of Benzothiophene-2-acetic Acid and Other Carboxylic Acids

Abstract In 1968 Gross and Costisella reported that certain substituted benzaldehydes could be converted to the corresponding arylacetic acids through the use of tetraethyl dimethylaminomethylenediphosphonate (1).1 Since that time, little synthetic attention has been given to this potentially useful reagent and the scope of its utility in transforming aldehydes into carboxylic acids containing one more carbon2 remains undefined.