Gold(III)-Catalyzed Selective Cyclization of Alkynyl Quinazolinone-Tethered Pyrroles: Synthesis of Fused Quinazolinone Scaffolds

A series
of 1,2- and 2,3-fused quinazolinones have been synthesized
in good to excellent yields through gold-catalyzed selective hydroarylations
of alkynyl quinazolinone-tethered pyrroles. The studies revealed that
1,2-fused quinazolinones were obtained through a 1,3-rearrangement
and sequential 6-exo-trig cyclization of N1-alkynyl
quinazolinone-tethered pyrroles, while N3-alkynyl quinazolinone-tethered
pyrroles went through 6-exo-dig or 7-endo-dig cyclizations directly to afford 2,3-fused quinazolinones. The fused
quinazolinones could be prepared at gram scale in three steps from
commercial ortho-aminobenzamide.