Novel 10-I-3 hypervalent iodine-based compounds for electrophilic trifluoromethylation

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.

A New Method for Preparation and Crystal Structure of (Trifluoromethyl)iodine Dichloride

(Trifluoromethyl)iodine dichloride (CF(3)ICl(2)) is synthesized by the reaction of (trifluoromethyl)iodine chloride fluoride (CF(3)I(Cl)F) with trimethylchlorosilane ((CH(3))(3)SiCl) at -40 degrees C. By using this route of preparation, in which CF(3)I(Cl)F undergoes a chlorine-fluorine exchange, CF(3)ICl(2) can be obtained in high purity and yield. CF(3)ICl(2) crystallizes in the orthorhombic space group Cmca with a = 6.990(1) Å, b = 7.985(1) Å, c = 21.177(1) Å, and eight formula units per unit cell. The final R indices [I > 2sigma(I)] are R(1) = 0.0341 and wR(2) = 0.0631. CF(3)ICl(2) is, in contrast to iodine trichloride (ICl(3)), monomeric, and its molecular structure is T-shaped with the CF(3) group in the equatorial position. The Raman, IR, and NMR spectra are also described.

Trifluoromethyl Hypobromite, CF(3)OBr

The synthesis and isolation of the hypobromite CF(3)OBr is reported. CF(3)OBr is formed besides Me(4)N(+)BrF(2)(-) by the reaction of CF(3)OCl and Me(4)N(+)Br(3)(-) via an addition-elimination mechanism. The initially formed solid, [2CF(3)OBr.Me(4)N(+)BrF(2)(-)], was characterized by (13)C and (19)F NMR, Raman, IR, and mass spectra. The hypobromite was separated from the solid by high-vacuum condensation onto a cold surface and characterized by matrix isolation multichannel Raman spectroscopy. An ab initio calculation was performed, and a force field and the torsional barrier of CF(3)OBr were calculated. The calculation predicts an eclipsed conformation with a rotional barrier of 3.4 kcal/mol. The photolytic decomposition of CF(3)OBr in the solid state and in an argon matrix was investigated.