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Silicon Tetrakis(trifluoromethanesulfonate): A Simple Neutral Silane Acting as a Soft and Hard Lewis Superacid
Author(s) -
Hermannsdorfer André,
Driess Matthias
Publication year - 2021
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.202103414
Subject(s) - trifluoromethanesulfonate , lewis acids and bases , chemistry , superacid , thioether , polymer chemistry , silane , halide , silicon , frustrated lewis pair , trifluoromethyl , medicinal chemistry , catalysis , organic chemistry , alkyl
A facile synthesis and isolation of pristine silicon tetrakis(trifluoromethanesulfonate), Si(OTf) 4 , is reported, acting as the first neutral silicon‐based Lewis superacid suitable towards soft and hard Lewis bases. Its OTf groups have a dual function: they are excellent leaving groups and modulate the degree of reactivity towards soft and hard Lewis bases. Exposed to soft Lewis donors, Si(OTf) 4 leads to [L 2 Si(OTf) 4 ] complexes (L=isocyanide, thioether and carbonyl compounds) with retention of all Si−OTf bonds. In contrast, it can cleave C−X bonds (X=F, Cl) of hard organic Lewis bases with a high tendency to form SiX 4 (X=F, Cl) after halide/triflate exchange. Most notable, Si(OTf) 4 allows a gentle oxydefluorination of mono‐ and bis(trifluoromethyl)benzenes, resulting in the formation of the corresponding benzoylium species, which are stabilized by the weakly coordinating [Si(OTf) 6 ] dianion.