Abstract: Provided are methods for synthesizing radiotracers, including no carrier added (n.c.a.) tracers suitable as PET scan tracers that contain a 18F—P bond. The radiolabeled products may be synthesized from precursors including phosphorus(V) and/or phosphorus (III) atoms bound to a suitable leaving group or group(s). For example, precursors incorporating a nitrophenoxy leaving group bound to a phosphorus(V) atom tend to exhibit an acceptable combination of stability and reactivity and also tend to allow the precursor compound(s) to be separated more easily from the 18F-labeled products. The methods disclosed herein for producing radiolabeled compounds incorporating a P—18F chemistry may particularly useful radiolabeling oligonucleotides, phospholipids, phosphorilated proteins, sugars and steroids for use as PET radiotracer compounds for medical imaging applications.