Synthesis, structure determination and (radio-) fluorination of novel functionalized phosphanes suitable for the traceless Staudinger ligation

An elegant and efficient synthesis approach for the preparation of novel benzoate and nicotinate containing phosphanes is presented. This reaction path has a broad substrate scope. Thus, various functionalized phosphanes were obtained in high yields using an esterification procedure under Steglich conditions. A facile blocking of the phosphorus with BH3 as protecting group enables a further derivatization of the benzoate residue. The prepared phosphane derivatives proved to be valuable labeling building blocks for the implementation of a (radio-)fluorination strategy. For this case, these compounds were applied for these labeling purposes using the traceless Staudinger Ligation. In this case, the preparation of a selection of azide-functionalized small organic and bioactive sample molecules and subsequent mild and selective (radio-) fluorination of these derivatives is demonstrated adopting this bioorthogonal ligation method.