A mild and selective photocatalytic C-H BF-fluorination reaction has been developed that provides direct access to BF-fluorinated amino acids. The biodistribution and uptake of three "F-labeled leucine analogues via LAT1 mediated transport in several cancer cell lines is reported. Positron emission tomography imaging of mice bearing PC3 (prostate) or U87 (glioma) xenografts using S-[F-18]-fluorohomoleucine showed high tumor uptake and excellent tumor -visualization, highlighting the utility of this strategy for rapid tracer discovery for oncology.