Selective iodine-Catalyzed Intermolecular Oxidative Amination of C(sp~3)-H Bonds with ortho-Carbonyl-Substituted Anilines to Give Quinazolines

摘要

Transition-metal-catalyzed intermolecular or intramolecular direct oxidative aminations of C(sp~3)—H bonds, including activated and unactivated C(sp~3)—H bonds, have emerged as important methods for C—N bond formations, because they are straightforward and have economic advantages over present procedures by employing prefunctionalized substrates (Scheme la).However, these aminations are restricted because of the toxicity of catalysts and their use of expensive transition metals as catalysts. Furthermore, only amides (acetamides or sulfonamides) were employed as coupling partners in most cases. Recently, Chang and Muniz have developed interesting metal-free aminations of benzylic and allylic C—H bonds, respectively, with sulfonamides in the presence of stoichiometric amounts of hyper-valent iodine (III) reagents. Although a transition metal was not required, large amounts of iodobenzene were generated as by-product, and the substrate scope was limited to sulfonamides (Scheme 1b). Therefore, a new, more efficient, and environmentally friendly catalyst for oxidative C(sp~3)—H amination with anilines is highly desirable.