65559-74-2Relevant articles and documents
BF3·Et2O as a metal-free catalyst for direct reductive amination of aldehydes with amines using formic acid as a reductant
Fan, Qing-Hua,Liu, Xintong,Luo, Zhenli,Pan, Yixiao,Xu, Lijin,Yang, Ji,Yao, Zhen,Zhang, Xin
supporting information, p. 5205 - 5211 (2021/07/29)
A versatile metal- and base-free direct reductive amination of aldehydes with amines using formic acid as a reductant under the catalysis of inexpensive BF3·Et2O has been developed. A wide range of primary and secondary amines and diversely substituted aldehydes are compatible with this transformation, allowing facile access to various secondary and tertiary amines in high yields with wide functional group tolerance. Moreover, the method is convenient for the late-stage functionalization of bioactive compounds and preparation of commercialized drug molecules and biologically relevant N-heterocycles. The procedure has the advantages of simple operation and workup and easy scale-up, and does not require dry conditions, an inert atmosphere or a water scavenger. Mechanistic studies reveal the involvement of imine activation by BF3and hydride transfer from formic acid.
Hydrogen-bond-assisted activation of allylic alcohols for palladium-catalyzed coupling reactions
Gumrukcu, Yasemin,Debruin, Bas,Reek, Joost N. H.
, p. 890 - 896 (2014/03/21)
We report direct activation of allylic alcohols using a hydrogen-bond-assisted palladium catalyst and use this for alkylation and amination reactions. The novel catalyst comprises a palladium complex based on a functionalized monodentate phosphoramidite ligand in combination with urea additives and affords linear alkylated and aminated allylic products selectively. Detailed kinetic analysis show that oxidative addition of the allyl alcohol is the rate-determining step, which is facilitated by hydrogen bonds between the alcohol, the ligand functional group, and the additional urea additive. Hydrogen Bond Rule(s): Direct activation of allylic alcohols and subsequent alkylation and amination reactions are reported. The new catalyst is based on functionalized palladium and phosphoramidite ligands to allow hydrogen bond-assisted activation. Kinetic data are in line with this mechanism as the oxidative addition is the rate-determining step.
Iron/amino acid catalyzed direct N-alkylation of amines with alcohols
Zhao, Yingsheng,Foo, Siong Wan,Saito, Susumu
supporting information; experimental part, p. 3006 - 3009 (2011/05/04)
(Chemical Equation Presented) Ironing it out: The straightforward N-alkylation using alcohols and iron/amino acid catalysis is described (see scheme). The reaction does not proceed by the conventional "borrowing hydrogen" mechanism, but appears to involve a substitution pathway (S N) at the sp3 carbon atom bearing the hydroxy group of the alcohol. Developing a catalyst that is effective at a near neutral pH was key to the successful N-alkylation.