102781-39-5Relevant articles and documents
Pendant Alkoxy Groups on N-Aryl Substitutions Drive the Efficiency of Imidazolylidene Catalysts for Homoenolate Annulation from Enal and Aldehyde
Kyan, Ryuji,Mase, Nobuyuki,Narumi, Tetsuo,Sato, Kohei
, p. 19031 - 19036 (2020/08/25)
Hydrogen-transfer in the tetrahedral intermediate generated from an imidazolylidene catalyst and α,β-unsaturated aldehyde forms a conjugated Breslow intermediate. This is a critical step affecting the efficiency of the NHC-catalyzed γ-butyrolactone formation via homoenolate addition to aryl aldehydes. A novel type of imidazolylidene catalyst with pendant alkoxy groups on the ortho-N-aryl groups is described. Catalyst of this sort facilitates the formation of the conjugated Breslow intermediate. Studies of the rate constants for homoenolate annulation affording γ-butyrolactones, reveal that introduction of the oxygen atoms in the appropriate position of the N-aryl substituents can increase the efficiency of imidazolylidene catalysts. Structural and mechanistic studies revealed that pendant alkoxy groups can be located close to the proton of the tetrahedral intermediate, thereby facilitating the proton transfer.
Electrogenerated Base (EG Base) Induced Hydroxymethylation of the Side Chain of Nitroalkylbenzenes with Paraformaldehyde
Torii, Sigeru,Murakami, Yasuo,Tanaka, Hideo,Okamoto, Koichi
, p. 3143 - 3147 (2007/10/02)
Hydroxymethylation of nitroalkylbenzenes with paraformaldehyde was accomplished by electrolysis in a (CH2O)n-DMF-Et4NOTs-(Pt electrode) system.The reaction was found to be catalytic (0.25 faraday/mol) and dependent on the electroreduction of formaldehyde and/or nitroalkylbenzene.A variety of nitroalkylbenzenes were transformed to their corresponding mono- and/or bishydroxymethylated derivatives in good yield.The product yield and selectivity were shown to depend on the order of reagent addition, solvent, supporting electrolyte, and structure of the starting nitroalkylbenzenes.A plausible mechanism of the generation of base catalysts (EG base) in electroreductive media is discussed.
