Preparation of Novel Fluoro Derivatives of Amine Cyanoboranes and Amine Carboxyborane Esters

摘要

Sonication of the amine mono- and dibro-mocarboxyborane esters or the amine mono- and dibro-mocyanoboranes with excess AgF results in rapid incorporation of fluorine by bromine /fluorine exchange to provide the difluoro derivatives of amine cyanoboranes and amine carboxyborane esters,1-10,in yields of 59- 70%.Bromination of the amine monofluorocyanoboranes and amine monofluorocarboxyborane ester derivatives successfully afforded the expected amine bromofluoro derivatives,11 and 12,in yields of 57-62%.This was confirmed by NMR shifts for all compounds.The pK_a value for the fluorinated amine carboxyborane 13 was determined and found to be 5.15 compared to 8.38 for Me_3N:BH_2COOH,in line with expectations.The molecular structure for compound 1 was determined by X-ray crystallography.