Synthesis, Isolation and Crystal Structures of the Metalated Ylides [Cy₃P‐C‐SO₂Tol]M (M = Li, Na, K)

Abstract

The preparation and isolation of the metalated ylides [Cy3PCSO2Tol]M (Cy1‐M) (with M = Li, Na, K) are reported. In contrast to its triphenylphosphonium analogue the synthesis of Cy1‐M revealed to be less straight forward. Synthetic routes to the phosphonium salt precursor Cy1‐H2 via different methods revealed to be unsuccessful or low‐yielding. However, nucleophilic attack of the ylide Cy3P = CH2 at toluenesulfonyl fluoride under basic conditions proved to be a high‐yielding method directly leading to the ylide Cy1‐H. Metalation to the yldiides was finally achieved with strong bases such as nBuLi, NaNH2, 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 C4‐symmetric structure with a (K4O4)2 octahedral prism as central structural motif. Upon deprotonation the P–C–S linkage undergoes a remarkable contraction typical for metalated ylides.

Au⋅⋅⋅H−C Hydrogen Bonds as Design Principle in Gold(I) Catalysis

“…L1 and L4 were prepared on gram scale as white solids by reaction of the metalated ylide Cy Y S ‐Li with Cy 2 PCl and i Pr 2 PCl in good yields of 75 % and 70 %, respectively. [11] …”

Phosphorus-ylides: powerful substituents for the stabilization of reactive main group compounds

“…Introduction of the PCy 3 group led to a remarkably reduced acidity of the ylide precursor, thus requiring stronger metal bases (benzyl potassium) for metallation. 38 Nonetheless, yldiide 15 was isolable on a gram-scale ( Fig. 6 ).…”

Au⋅⋅⋅H−C Hydrogen Bonds as Design Principle in Gold(I) Catalysis

“…Additionally, the iso ‐propyl‐derivative of L1 , Cy Y S P i Pr 2 ( L4 ) was synthesized to evaluate the influence of the lower steric bulk of the smaller alkyl group on the catalytic ability. L1 and L4 were prepared on gram scale as white solids by reaction of the metalated ylide Cy Y S ‐Li with Cy 2 PCl and i Pr 2 PCl in good yields of 75 % and 70 %, respectively [11] …”

“…To access this ligand, the metalated ylide Cy Y SF ‐Li first had to be synthesized. By analogy to the procedure reported for Cy Y S ‐Li, [11] the protonated precursor Cy Y SF ‐H was prepared in a one‐pot reaction from the easily accessible phosphonium salt [Cy 3 P‐CH 3 ]I and the commercially available perfluorobutanesulfonyl fluoride in the presence of two equiv of KHMDS in a very good yield of 83 % (Scheme 2). Cy Y SF ‐H was isolated as a pale‐yellow powder and fully characterized (see SI for details).…”