Abstract: | Four complexes of MCl4 (M=Ti, Zr, Hf) with the hypervalent trifluoromethyl iodine reagent trifluoromethyl‐1,3‐dihydro‐3,3‐dimethyl‐1,2‐benziodoxole ( 1 ,=L) are described. With TiCl4, an I?O bond cleavage occurs, leading to the formation of the trifluoromethyliodonium alcoholate complexes Ti2Cl6(L)4]Cl2 ( 2 a ) and Ti2Cl8(L) ( 2 b ). Reactions with ZrCl4 and HfCl4 form the complexes ZrCl4(L)2 ( 3 ) and HfCl4(L)2 ( 4 ), respectively, wherein the original I?O bond is retained and elongated compared to that in free 1 . Therefore, the reactivity of 1 can be easily and practically fine‐tuned by addition of different metal chlorides, following the order ZrCl4/HfCl4<TiCl4<2 TiCl4. Complexes 2 a , 3 , and 4 are remarkably bench‐stable forms of activated reagent 1 , while 2 b is readily accessible in situ. 2 a and 2 b represent the first “real” trifluoromethyliodonium reagents derived from iodanes, that is, with the I?O bond being completely cleaved. The new complexes were shown to be useful for the trifluoromethylation of para‐toluenesulfonate under aprotic conditions. |