Abstract: The present disclosure provides novel selective phosphatase inhibitor compounds based on illudalic acid. The present disclosure provides a streamlined method of synthesizing illudalic acid and a method for synthesizing phosphatase inhibitor compounds. The method of this invention provides convergent benzannulation of ?-keto amides and esters, followed by a one-pot reduction/hydrolysis sequence. The concise synthetic approach provided by this invention enables rapid assembly of illudalog compounds of this invention that are potent protein tyrosine phosphatase receptor-type D (PTPRD) inhibitors.