Trimethyl sulfur trifluoride

Diethylaminotrimethylsilane Silanamine, N,N-diethyl-1,1,1-trimethyl- (8,9) (996-50-9) Diethylaminosulfur trifluoride Sulfur, (diethylaminato)trifluoro- (9) (38078-09-0)... 

Acidic behavior is thus the acceptance of an electron pair from an electron donor, this donor being called a Lewis base. There are three classes of Lewis acids that are important the first class consists of compounds having less than a full octet of electrons. A typical member of this class is trimethyl boron, B(CH3)3. Boron trifluoride and sulfur trioxide may be drawn with less than a full octet of electrons on the respective central atoms and are Lewis acids also. 

Fluoro-A -sulfanes, such as sulfur tetrafluoride, diethylaminosulfur trifluoride (DAST) ° and piperidinosulfiir trifluoride,are able to selectively substitute the trimethyl-siloxy group by fluorine under mild conditions. 

The addition takes place according to Markownikoff s rule. The addition of carbo lic acida to the double bonds of isobutylene and trimethyl-ethylene gives tertiary esters. A true equilibrium independent of sulfuric acid concentrations is established in the exothermic reaction. The addition does not go well with ethylene, but goes well with many of the higher alkenes, particularly with some of the terpenes. To avoid the polymerizing effects of sulfuric acid, various other catalysts, such as sulfonic acids, triethylamine, hydrofluoric acid, boron trifluoride, and cuprous chloride have been used. The addition may take place at room temperature or higher and is aided by pressure. The vapors of the acid and hydrocarbon may be passed over catalysts, such as activated carbon, heteropoly acids, or metal phosphates. ... 

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