Stetter-type compounds

While j0-hydroxyketones and j0-hydroxyamides have been accessed via a novel NHC-catalysed silyl-Reformatsky reaction between aldehydes and a-trimethylsilylcarbonyl compounds, 0-formylketones have been prepared from enones via a Stetter-type reac-... 

As early as 1955, Stetter and Roos (123) recognized compounds of this type and synthesized bis(N, N -tetramethylene benzidine (127) (Figure 2.52). They observed that (127) tenaciously retained stoichiometric amounts of benzene or dioxane (1 1), even after drying at 80"" C for 5h, when crystallized from... 

Imidazolium-type room temperature ionic liquids (RTTLs) have been used for the Stetter reaction, affording the desired 1,4-dicarbonyl compounds (e.g. 167) in good yields together with the benzoin (e.g. 168). Thiazolium salts and EtsN are efficient catalysts for this reaction performed in ionic liquid. The possibility to recycle and reuse the solvent has been demonstrated, although it was not possible to recycle the thiazolium catalyst (Anjaiah et al. 2004). 

---