3300-51-4Relevant articles and documents
Cobalt-Catalyzed Hydrogenative Transformation of Nitriles
Zhang, Shaoke,Duan, Ya-Nan,Qian, Yu,Tang, Wenyue,Zhang, Runtong,Wen, Jialin,Zhang, Xumu
, p. 13761 - 13767 (2021/11/17)
Here, we report the transformation of nitrile compounds in a hydrogen atmosphere. Catalyzed by a cobalt/tetraphosphine complex, hydrogenative coupling of unprotected indoles with nitriles proceeds smoothly in a basic medium, yielding C3 alkylated indoles. In addition, the direct hydrogenation of nitriles under the same conditions yielded primary amines. Isotope labeling experiments, along with a series of control experiments, revealed a reaction pathway that involves nucleophilic addition of indoles and 1,4-reduction of a conjugate imine intermediate. Different from reductive alkylation of indoles under an acidic condition, E1cB elimination is believed to occur in this base-promoted hydrogenative coupling reaction.
Zirconium-hydride-catalyzed site-selective hydroboration of amides for the synthesis of amines: Mechanism, scope, and application
Han, Bo,Jiao, Haijun,Wu, Lipeng,Zhang, Jiong
, p. 2059 - 2067 (2021/09/02)
Developing mild and efficient catalytic methods for the selective synthesis of amines is a longstanding research objective. In this respect, catalytic deoxygenative amide reduction has proven to be promising but challenging, as this approach necessitates selective C–O bond cleavage. Herein, we report the selective hydroboration of primary, secondary, and tertiary amides at room temperature catalyzed by an earth-abundant-metal catalyst, Zr-H, for accessing diverse amines. Various readily reducible functional groups, such as esters, alkynes, and alkenes, were well tolerated. Furthermore, the methodology was extended to the synthesis of bio- and drug-derived amines. Detailed mechanistic studies revealed a reaction pathway entailing aldehyde and amido complex formation via an unusual C–N bond cleavage-reformation process, followed by C–O bond cleavage.
1,3-Diphenyldisiloxane Enables Additive-Free Redox Recycling Reactions and Catalysis with Triphenylphosphine
Buonomo, Joseph A.,Cole, Malcolm S.,Eiden, Carter G.,Aldrich, Courtney C.
, p. 3583 - 3594 (2020/09/15)
The recently reported chemoselective reduction of phosphine oxides with 1,3-diphenyldisiloxane (DPDS) has opened up the possibility of additive-free phosphine oxide reductions in catalytic systems. Herein we disclose the use of this new reducing agent as an enabler of phosphorus redox recycling in Wittig, Staudinger, and alcohol substitution reactions. DPDS was successfully utilized in ambient-temperature additive-free redox recycling variants of the Wittig olefination, Appel halogenation, and Staudinger reduction. Triphenylphosphine-promoted catalytic recycling reactions were also facilitated by DPDS. Additive-free triphenylphosphine-promoted catalytic Staudinger reductions could even be performed at ambient temperature due to the rapid nature of phosphinimine reduction, for which we characterized kinetic and thermodynamic parameters. These results demonstrate the utility of DPDS as an excellent reducing agent for the development of phosphorus redox recycling reactions.
