Abstract
The preparation and isolation of the metalated ylides [Cy(3)PCSO(2)Tol]M ( (Cy)1-M) (with M = Li, Na, K) are reported. In contrast to its triphenylphosphonium analogue the synthesis of (Cy)1-M revealed to be less straight forward. Synthetic routes to the phosphonium salt precursor (Cy)1-H(2) via different methods revealed to be unsuccessful or low-yielding. However, nucleophilic attack of the ylide Cy(3)P = CH(2) at toluenesulfonyl fluoride under basic conditions proved to be a high-yielding method directly leading to the ylide (Cy)1-H. Metalation to the yldiides was finally achieved with strong bases such as nBuLi, NaNH(2), or BnK. In the solid state, the lithium compound forms a tetrameric structure consisting of a (C-S-O-Li)(4) macrocycle, which incorporates an additional molecule of lithium iodide. The potassium compound forms a C (4)-symmetric structure with a (K(4)O(4))(2) octahedral prism as central structural motif. Upon deprotonation the P-C-S linkage undergoes a remarkable contraction typical for metalated ylides.