Exploring the versatility of the amidation of aryl acid fluorides using the germylamines R3GeNMe2.

Abstract

The formation of amide bonds is an important process since this linkage is an essential component in proteins, pharmaceuticals, and other medicinally and biologically significant molecules. Recently, it was demonstrated that germylamines R3GeNR'2 were useful reagents for the conversion of acid fluorides to amides. This transformation occurs readily at room temperature and has a low activation energy. In the present study, the versatility of this amidation reaction with aryl acid fluorides is investigated. A series of thirteen acid fluorides with various substituents on the aromatic ring were reacted with the germylamine Ph3GeNMe2 and twelve of these were converted to the corresponding amides in high yields, the exception being 1,4-benzenedicarbonyl difluoride. The germylamines Bun3GeNMe2 and Pri3GeNMe2 also could be used for this interconversion, and both of these species successfully converted 1,4-benzenedicarbonyl difluoride to the corresponding amide. In addition, the crystal structure of Ph3GeNMe2 is reported. This represents one of only three crystallographically characterized germylamines. The synthesis and 19F NMR characterization of three fluorogermanes R3GeF (R = Bun, Pri, and Mes) are also reported herein.