Mild and Efficient Pentafluorophenylammonium Triflate (PFPAT)-Catalyzed C-Acylations of Enol Silyl Ethers or Ketene Silyl (Thio)Acetals with Acid Chlorides
A pentafluorophenylammonium triflate (PFPAT) catalyst (5 mol %) successfully promoted C-acylation of enol silyl ethers with acid chloride to produce various beta-diketones (12 examples; 62-92% yield). Similarly, C-acylation of ketenesilylacetals or ketenesilyl thioacetals (i.e., crossed Claisen condensation) proceeded smoothly to provide not only alpha-monoalkylated beta-keto (thio)esters but also
Reductive Ti-crossed Claisen Condensation between Methyl α-Bromocarboxylates and Acid Chlorides Utilizing a TiCl<sub>4</sub>–PPh<sub>3</sub>–<i>N</i>-Methylimidazole Reagent
Reductive Ti-crossed Claisen condensation between methyl α-bromocarboxylates and acid chlorides utilizing a TiCl4–PPh3–N-methylimidazole reagent proceeded smoothly to give the α-monosubstituted and...
利用 TiCl4–PPh3–N-甲基咪唑试剂,α-溴代羧酸甲酯和酰氯之间的还原性 Ti 交叉克莱森缩合反应顺利进行,得到 α-单取代和...
Powerful Ti-Crossed Claisen Condensation between Ketene Silyl Acetals or Thioacetals and Acid Chlorides or Acids
[Structure: see text] A powerful Ti-crossed Claisen condensation between ketene silyl acetals (KSAs) and acid chlorides was successfully performed to give alpha-monoalkylated esters and thermodynamically unfavorable (less accessible) alpha,alpha-dialkylated beta-keto esters in good yield (46 examples; 41-98% yield). A closely related reaction between ketene silyl thioacetals (KSTAs) and acid chlorides also