Regioselective synthesis of spiro quinazolinones via sequential hydroalkoxylation and intramolecular amide-cyclization of alkynol ureas

Abstract

A TfOH-mediated, metal-free protocol for the synthesis of spiro-furan/pyran quinazolinones through a cascade hydroalkoxylation and intramolecular amide-cyclization reaction of alkynol ureas has been unveiled. This methodology facilitates the generation of highly functionalized spiro-heterocycles with remarkable yields and exclusive regioselectivity. Furthermore, the applicability of the strategy extends to the synthesis of spiro-pyrrolidine quinazolinones. Finally, post-synthetic modification incorporates bromide functionality into the synthesized spiro-heterocycle.