Bronsted Acid-Promoted Sequential Hydroarylation-Hydroamidation of Arene-Tethered 1-(2-Alkynylphenyl)ureas: Direct Access to 4,4-Spiro-3,4-dihydro-2-(1H)-quinazolinones

A Bronsted acid-promoted approach to 4,4-sipro-3,4-dihydro-2-(1H)-quinazolinones from arene-tethered 1-(2-alkynylphenyl) ureas has been developed. The reaction is initiated by intramolecular hydroarylation followed by hydroamidation, assisted by intramolecular proton transfer from the protonated urea moiety. A variety of tethering atoms, including carbon, oxygen, sulfur, and protected nitrogen are compatible with the reaction conditions.