Trifluoromethyl Group 2B Compounds: Bis(trifluoromethylcadmium*Base. New, More Powerful Ligand-Exchange Reagents and Low Temperature Difluorocarbene Sources

Article abstract of DOI:10.1021/ja00401a015

Lewis base adducts of bis(trifluoromethyl)cadmium have been isolated from the interaction of bis(trifluoromethyl)mercury with dimethylcadmium in solvents like THF, glyme, diglyme, or pyridine.Lewis base exchange, for example, pyridine for glyme, occurs upon dissolution of the glyme adduct, (CF3)2Cd*g, g = CH3OCH2CH2OCH3, in pyridine.The (CF3)2Cd*base species are shown to be much more reactive than (CF3)2Hg since the cadmium compounds are reactive at temperatures at least 100 deg C below that required for the mercurial.At ambient temperatures ligand exchanges between SnBr4 or GeI4 and (CF3)2Cd*glyme are found to be most convenient preparations of (CF3)4Sn (66percent yield) or (CF3)4Ge (43percent yield); the formation of (CF3)3P from the reaction of PI3 also occurs, but the amounts isolated are smaller.The reaction of acyl halides with (CF3)2Cd*g proceeds at subambient temperature to yield the acyl fluoride, ca. 90percent yield, and difluorocarbene which can be trapped stereospecifically by, e.g., cis-2-butene at -30 deg C.Difluorocarbene formation occurs at temperatures at least as low as -78 deg C.