N‑Heterocycle-Forming Amino/Carboperfluoroalkylations of Aminoalkenes by Using Perfluoro Acid Anhydrides: Mechanistic Studies and Applications Directed Toward Perfluoroalkylated Compound Libraries

• Published in: Journal of organic chemistry Vol. 82; no. 23; pp. 12539 - 12553
• Main Authors: Kawamura, Shintaro, Dosei, Kento, Valverde, Elena, Ushida, Kiminori, Sodeoka, Mikiko
• Format: Journal Article
• Language: English
• Published: WASHINGTON American Chemical Society 01.12.2017; Amer Chemical Soc
• Subjects: Chemistry; Chemistry, Organic; Physical Sciences; Science & Technology; COPPER-CATALYZED TRIFLUOROMETHYLATION; BIS(TRIFLUOROACETYL) PEROXIDE; FREE-RADICAL PERFLUOROALKYLATION; CONSTRUCTION; AMINOTRIFLUOROMETHYLATION; BOND FORMATION; AZIRIDINES; DERIVATIVES; CYCLIZATION; UNACTIVATED ALKENES
• ISSN: 0022-3263; 1520-6904
• DOI: 10.1021/acs.joc.7b02307

This work describes a practical and efficient method for synthesizing a diverse array of perfluoroalkylated amines, including N-heterocycles, to afford perfluoroalkylated chemical libraries as potential sources of drug candidates, agrochemicals, and probe molecules for chemical-biology research. Perfluoro acid anhydrides, which are commonly used in organic synthesis, were employed as a perfluoroalkyl source for intramolecular amino- and carbo-perfluoroalkylations of aminoalkenes, affording perfluoroalkylated N-heterocycles, including: aziridines, pyrrolidines, benzothiazinane dioxides, indolines, and hydroisoquinolinones. Diacyl peroxides were generated in situ from the perfluoro acid anhydrides with urea·H2O2, and allowed to react with aminoalkenes in the presence of copper catalyst to control the product selectivity between amino- and carbo-perfluoroalkylations. To illustrate the synthetic utility of bench-stable trifluoromethylated aziridine, which was prepared on a gram scale, we used it to synthesize a wide variety of trifluoromethylated amines including complex molecules, such as trifluoromethylated tetrahydroharmine and spiroindolone. A mechanistic study of the role of the copper catalyst in the aminotrifluoromethylation of allylamine suggested that Cu­(I) accelerates CF3 radical formation via decomposition of diacyl peroxide, which appears to be the turnover-limiting step, while Cu­(II) controls the product selectivity.