Synthesis, Isolation and Crystal Structures of the Metalated Ylides [Cy<sub>3</sub>P‐C‐SO<sub>2</sub>Tol]M (M = Li, Na, K)
Heidar Darmandeh, Thorsten Scherpf, Kai‐Stephan Feichtner, Christopher Schwarz, Viktoria H. Gessner
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 n BuLi, 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.