Multicomponent Aromatic and Benzylic Mannich Reactions through C−H Bond Activation

Abstract

Multicomponent Mannich reactions through C−H bond activation are described. These transformations allowed for the straightforward generation of densely substituted benzylic and homo‐benzylic amines in good yields. The reaction involves a reaction between two transient species: an organometallic species, generated by transition‐metal‐catalyzed sp2 or sp3 C−H bond activation and an in situ generated imine. The use of an acetal as an aldehyde surrogate was found essential for the reaction to proceed. The process could be successfully applied to RhIII‐catalyzed sp2 C−H bond functionalization and extended to CuII‐catalyzed sp3 C−H bond functionalization.

Dispersion Forces Drive the Formation of Uranium–Alkane Adducts

“…The selective activation of carbon–hydrogen bonds is a great challenge for synthetic chemists. − This activation reaction is essential to allow access to natural gas resources and use them as feedstocks for fuels and chemicals. − In carbon–hydrogen-activation reactions, a carbon–hydrogen bond is broken and replaced with a carbon–carbon, carbon–oxygen, or carbon–nitrogen bond. This is typically achieved by using metal catalysis, which forms an intermediate with the hydrocarbon molecule before allowing it to undergo additional reactions to produce a functionalized molecule.…”

Decarboxylative Mannich Reactions with Substituted Malonic Acid Half-Oxyesters

“…Moreover, none of the above-mentioned contributions exploit the intrinsic multicomponent potential character of the Mannich reaction . In continuation with our work on Mannich reactions , and substituted MAHOs, we disclose herein the development of organocatalyzed decarboxylative Mannich reactions involving SMAHOs (Scheme ).…”

Rhodium(iii)-catalyzed three-component C(sp2)–H activation for the synthesis of amines

“…In the presence of a rhodium catalyst, the desired product was obtained with less than 30% isolated yield. 13 Afterwards, they used acetals instead of aldehydes as substrates to enable the reaction to proceed smoothly (Scheme 1c). This contribution represents a valuable synthetic tool and leaves ample opportunities to develop directly three-component C-H bond activation to synthesize amines.…”

“…Rhodium was first selected as the catalyst, and TsOH and HFIP were selected as the acid and solvent; meanwhile, due to the inhibitory effect of water on the reaction, a molecular sieve was added, and the desired product 4a was obtained with a 31% yield at 70 1C in 18 h (Table 1, entry 1), which is consistent with the results of Tania's work. 13 Based on our previous work, copper could significantly improve reactivity in rhodium-catalyzed aryl substitution amination reactions. 14 The addition of copper salts was conducted for further optimization of the conditions.…”