A more detailed analysis of the studied building block performance revealed several tendencies. In particular, the average product yield was affected by the compound's fluorination pattern in a following manner: non-fluorinated (60%)  4,4-difluorinated (59%) > 3,3-difluorinated (47%) (Figure ). We have also evaluated 2,2-difluorocycloalkanecarboxylic acids (C4 to C7) in the reaction with heterocycles under the standard conditions; although minor amounts of the target products were detected by LC-MS, none of them could be isolated in pure form. Cycloheptane-containing trifluoroborates 2{7-10} showed relatively poor results as compared to other substrates.