[ 11 C]Methylenetriphenylphosphorane, a new 11 C‐precursor, used in a one‐pot wittig synthesis of [β‐ 11 C]styrene

Preparation of [ 11 C]methyltriphenylphosphonium iodide and the in situ generation of [ 11 C]methylenetriphenylphosphorane directly from [ 11 C]methyl iodide, is described. Using this one‐pot preparation, [β‐ 11 C]styrene was synthesized conveniently, fast and with a minimum of manual handling. The synthesis was performed by using [ 11 C]methyl iodide, triphenylphosphine, epichlorohydrin and benzaldehyde in tetrahydrofurane/o‐dibromobenzene, with a synthesis time of 40 min (counted from the end of [ 11 C]methyl iodide transfer), a radiochemical yield of 80–90% of [β‐ 11 C]styrene and a specific radioactivity, of 100MBq/μmol. In a typical experiment starting with 960 MBq 11 C‐methyl iodide, 200 MBq of [β‐ 11 C]styrene was obtained within 42 min.