Novel 10-I-3 Hypervalent Iodine-Based Compounds for Electrophilic Trifluoromethylation

• Published in: Chemistry : a European journal Vol. 12; no. 9; pp. 2579 - 2586
• Main Authors: Eisenberger, Patrick, Gischig, Sebastian, Togni, Antonio
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 08.03.2006; WILEY‐VCH Verlag; Wiley
• Subjects: Chemistry; Chemistry, Multidisciplinary; Chlorofluorocarbons, Methane - chemistry; Crystallography, X-Ray; hypervalent compounds; iodine; Iodine Compounds - chemistry; Physical Sciences; Science & Technology; Solvents; trifluoromethylation; umpolung; ORGANIC-CHEMISTRY; REAGENTS; ENOL ETHERS; hypervalent compounds; umpolung; PERFLUOROALKYLATION; RAY CRYSTAL-STRUCTURE; SALT SYSTEM; SECONDARY ALCOHOLS; SPECTROSCOPIC CHARACTERIZATION; FLUORINE; iodine; trifluoromethylation; POLYVALENT IODINE
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.200501052

The synthesis of a new family of 10‐I‐3 hypervalent iodine compounds is described in which the CF3 functionality participates directly in the hypervalent bond. These materials are accessible by nucleophilic ligand substitution at iodine using Me3SiCF3 in the presence of a substoichiometric amount of fluoride. The expected T‐shaped geometry at iodine was verified by X‐ray crystallographic analyses of three of the products (1‐trifluoromethyl‐1,2‐benziodoxol‐3‐(1 H)‐one and two substituted 1‐trifluoromethyl‐1,3‐dihydro‐1,2‐benziodoxoles). Preliminary results for the direct electrophilic transfer of the trifluoromethyl moiety onto organic nucleophiles show modest reactivity in polar aprotic solvents under relatively mild conditions. The overall process can be understood as a formal umpolung of the CF3 group. Nucleophilic ligand displacement with “CF3” is a versatile method for synthesis of the title compounds, which act as reagents in the electrophilic α‐trifluoromethylation of β‐ketoesters (see scheme). The overall process can be seen as a formal umpolung of the CF3 group.