Synthesis, isolation and crystal structures of the metalated ylides [Cy${}_3$P-C-SO${}_2$Tol]M (M = Li, Na, K)

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. (© 2020 The Authors. Published by Wiley‐VCH Verlag GmbH and Co. KGaA.)