Ruthenium‐Catalyzed Intermolecular Cyclization and N‐Methylation of Salicyl N‐Tosylhydrazones

Abstract

3‐(2,2‐dichloroacetyl)‐2H‐Chromen‐2‐ones were prepared by treating salicyl N‐tosylhydrazones with ethyl 4,4,4‐trichloro‐3‐oxobutanoate in presence of catalytic amount of La(OTf)3 and RuCl3 ⋅ 3H2O for the first time. The chromenones were formed through C‐C, C‐O bond formations, detosylation and more importantly dechlorination protocol. One of the compound 3‐(2,2‐dichloroacetyl)‐6‐methyl‐2H‐chromen‐2‐one structure was confirmed by single‐crystal X‐ray analysis. Further, salicyl N‐tosylhydrazones when treated with dimethyl (1‐diazo‐2‐oxopropyl)‐phosphonate (Bestmann‐Ohira reagent) in presence of K2CO3 and RuCl3 ⋅ 3H2O provided (E)‐N′‐(2‐hydroxybenzylidene)‐N,4‐dimethylbenzenesulfono hydrazide.

Cu@CuFe2O4 nanoparticles catalyzed oxidative functionalization of alkynes: Access to α,α‐dichloro ketones

“…Consequently, there has been a concerted effort to develop new synthetic methods by using α,α ‐dihaloketones as starting material in recent decades. Furthermore, traditional transformations such as oxidation, reduction, and C‐C bond formation, and innovative methods such as photocatalytic or electrocatalytic reactions have been explored 15–31 . For example, Madabhushi reported that the a,a ‐dichloro arylketones were obtained through the oxidation of terminal alkyne, respectively (Scheme a) 32,33 .…”

“…Furthermore, traditional transformations such as oxidation, reduction, and C-C bond formation, and innovative methods such as photocatalytic or electrocatalytic reactions have been explored. [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31] For example, Madabhushi reported that the a,a-dichloro arylketones were obtained through the oxidation of terminal alkyne, respectively (Scheme a). 32,33 In the realm of photocatalytic reactions, Handa and Jiang demonstrated the transformation of alkyne to a,adichloro arylketones under photocatalytic conditions (Scheme b).…”