Rapid Coupling of Methyl Iodide with Aryltributylstannanes Mediated by Palladium(0) Complexes: A General Protocol for the Synthesis of ¹¹CH₃‐Labeled PET Tracers

Abstract

Abstract The reaction of methyl iodide and (excess) aryltributylstannane to give a methylarene has been studied with the focus on the realization of rapid coupling for incorporation of short‐lived radionuclides into bioactive organic compounds. The coupling of methyl iodide with tributylphenylstannane (40 equiv) is accomplished in >90% yield within 5 min at 60°C with a tri‐ o ‐tolylphosphine‐bound, coordinatively unsaturated Pd 0 complex together with a Cu I salt and K 2 CO 3 in DMF. This protocol is applicable to a variety of homo‐ and heteroaromatic tin compounds, to give the corresponding methylated derivatives. The effects of the tri‐ o ‐tolylphosphine ligand, a Cu(I) salt, and DMF are discussed. This new protocol provides a firm chemical basis for the synthesis of 11 CH 3 ‐incorporated PET tracers.