Novel 4- and 7-Sulfonylated 2-Substituted Benzoxazoles

The efficient synthesis of sulfonylated benzoxazoles at positions C4 or C7 is reported. The condensation reactions involve original anilide acetal reagents which, upon acid catalysis, allow an easy cyclization reaction with the sulfonylated o-aminophenol partners. This method circumvents the classical use of orthoesters which drawback is the limited access to aromatic reagents