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Angew Chem Int Ed Engl. 2012 Aug 6;51(32):8077-81.
Yan Y, Zhang Y, Feng C, Zha Z, Wang Z.
Hefei National Laboratory for Physical Sciences at Microscale, and Department of Chemistry, University of Science and Technology of China, Hefei, 230026 P. R. China.
Abstract
Access to quinazolines: The selective amination of C(sp3)H bonds adjacent to nitrogen or oxygen atoms of N-alkylamides, ethers, or alcohols with ortho-carbonyl-substituted anilines constitutes the first step in a tandem annulation that leads to quinazolines in good to excellent yields (see scheme; NIS=N-Iodosuccinimide, TBHP=tert-butyl hydroperoxide). The selectivity of the amination of primary and secondary CH bonds is also noteworthy (left: >3:1, right: >99:1).
Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Addition Information:
We developed an iodine-catalyzed oxidative amination of C(sp3)-H bonds adjacent to nitrogen or oxygen atoms for the synthesis of quinazolines from orthocarbonyl-substituted anilines, ammonia, and solvents, such as N-alkylamides, ethers, and alcohols. A 13C-labeling experiment unambiguously established that the additional carbon atom of quinazolines was derived from the N-methyl group of N-methylamide. Notably, this is the first example of a combination of inorganic nitrogen sources and organic solvents for construction of heterocycles. Moreover, KIE experiment also indicated that the C-H bond cleavage was the rate-determining step. Compared with previous reports, this novel protocol is distinguished by 1) the lack of expensive transition metals, 2) operational simplicity, 3) the fact that an inert atmosphere or dry solvents are not required, 4) a wide tolerance of various functional groups, and 5) the production of alcohol and water as the only waste. More importantly, the selectivity of the reactions between primary and secondary C-H bonds was the first observed in oxidative C(sp3)-H aminations.
