Chromium trifluoromethyl derivatives

Halogenomethylpyrroles have been oxidized with lead(IV) salts or by chromium trioxide to yield the formylpyrroles, whilst catalytic hydrogenolysis or zinc-acetic acid reduction produces the 2-methylpyrroles (B-77MI30504). The methyl derivatives are also obtained by hydride reduction of trifluoromethyl-pyrroles and -indoles, and trifluoromethylindoles are converted into the carboxylic esters by ethanol under basic conditions (74JOC1836). 

Fluorine atoms in electron-deficient benzene derivatives, such as l-fluoro-2-nitroben-zene,149-150 l-fluoro-4-nitrobenzene.151 153 2-fluorobenzaldchyde,154"156 2-fluoroaceto-phenone,155156 4-fluoroacetophenonc,157 2-fluorobenzophenone.156 2- and 4-fluorobenzoni-trile,158 and 4-fluorophenyl trifluoromethyl sulfone,152,159 are easily substituted by N-nucleophiles. Even fluorine in electron-deficient sandwich complexes, such as tricarbonyl(t/6-fluoro-benzene)chromium (3), is substituted by amines.160161... 

Dimerization of sulfene yields disulfone 546, whose protons are readily replaced by deuterium, bromine, or trimethylsilyl groups. Sulfone 546 reacts with 2,6-dimethyl-4-pyrone to give an exo-methylene derivative and it may be tetra-methylated. Other disulfones are obtained by oxidation of 1,3-dithietanes with potassium permanganate or chromium trioxide-fuming nitric acid for resistant dithietanes. As mentioned above, peracetic acid oxidizes a disulfoxide, mono-sulfone, or a monosulfone-monosulfoxide to the disulfone 546. 57b,iii3a 2,2,4,4-Tetra(trifluoromethyl)-l,3-dithietane 537 is oxidized only to the monosulfone 547, even with chromium trioxide-hot, fuming nitric acid the disulfone is only... 

---