Divergent Synthesis of Trifluoromethyl-Substituted 1,2-Dihydroquinoxalines and Diimines by Cascade Reactions of CF₃–Imidoyl Sulfoxonium Ylides with Azo Compounds

Abstract

A base-mediated cascade reaction of CF3-imidoyl sulfoxonium ylides and azo compounds has been achieved, allowing for facile access to trifluoromethyl-substituted 1,2-dihydroquinoxalines and diimines in moderate to excellent yields. Noteworthy is that the unusual N–N bond cleavage and rearrangement of azo compounds are involved in the transformations.

Carbonylative synthesis of 2-(trifluoromethyl)quinazolin-4(3H)-ones from trifluoroacetimidoyl chlorides and amines based on an activated carbon fiber supported palladium catalyst

“…40,41 This is primarily due to the profusion of functional groups present on the fiber surfaces, which serve as anchoring points for the catalyst. Encouraged by our interest in heterogeneous catalysts 42–44 and facile construction of trifluoromethyl-containing heterocycles, 26,45–53 we herein develop a heterogeneous catalytic carbonylative cyclization reaction of trifluoroacetimidoyl chlorides with amines based on a palladium supported on ACFs (Pd/ACFs) catalyst for the synthesis of 2-(trifluoromethyl)quinazolin-4(3 H )-ones in moderate to excellent yields with a smaller amount of palladium catalyst loading.…”

Rhodium(III)-Catalyzed Coupling of Quinolin-8-carboxaldehydes with CF3–Imidoyl Sulfoxonium Ylides by Chelation-Assisted C(sp2)-H Bond Activation for the Synthesis of Trifluoromethyl-Substituted Enaminones

“…At this stage, there are no successful examples regarding TFISYs-involved aldehyde C­(sp 2 )–H bond activation to afford trifluoromethyl-functionalized carbonyl derivatives. In continuation of our interest in C–H activation reactions and transformations of TFISYs, we herein present a rhodium­(III)-catalyzed coupling of quinolin-8-carboxaldehydes with TFISYs via aldehydic C­(sp 2 )–H imidoylmethylation and the following tautomerization, producing an array of synthetically and biologically important CF 3 -substituted enaminones in moderate to excellent yields (Scheme d). Although CF 3 -substituted enaminones could be prepared by the coupling of trifluoroacetimidoyl chlorides with methyl ketones, the obvious limitations still remain, such as harsh reaction conditions involving the use of strong base and low temperature, narrow substrate scope, and inferior yields.…”