Highly Chemoselective Hydrogenation of Cyclic Imides to ω-hydroxylactams or ω-hydroxyamides Catalyzed by Iridium Catalysts

The chemoselective hydrogenation of unsaturated compounds has been a powerful tool for both synthetic chemistry and chemical industry. The achievement of chemoselectivity among different functionalities with a single catalyst has been a challenge for transition metal-catalyzed hydrogenation. In this paper, iron tetraphosphine complexes show high catalytic efficiency for a variety of polar unsaturated substrates such as aldehydes, ketones, enones, nitroarenes and N-heteroaromatics. Without an N-H group on the catalyst, the chemoselectivity was controlled precisely by the reaction temperature. The catalytic efficiency, chemoselectivity and robustness of this Fe/P4N2 catalyst found its merit in the preparation of several important drug intermediates. A diamagnetic trans-iron dihydride complex, formed under the reaction conditions, was supposed to be an on-cycle catalytically active species.<br>

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Iron-Catalyzed Homogeneous Hydrogenation with Precise Temperature-Governed Chemoselectivity.

10.26434/chemrxiv.14663454 ◽

2021 ◽

Author(s):

Ya-Nan Duan ◽

Yiqun Zeng ◽

ZhiKai Cui ◽

Jialin Wen ◽

Xumu Zhang

Keyword(s):

Transition Metal ◽

Chemical Industry ◽

Catalytic Efficiency ◽

Active Species ◽

Homogeneous Hydrogenation ◽

Reaction Conditions ◽

Chemoselective Hydrogenation ◽

Catalytically Active ◽

Metal Catalyzed ◽

Important Drug

The chemoselective hydrogenation of unsaturated compounds has been a powerful tool for both synthetic chemistry and chemical industry. The achievement of chemoselectivity among different functionalities with a single catalyst has been a challenge for transition metal-catalyzed hydrogenation. In this paper, iron tetraphosphine complexes show high catalytic efficiency for a variety of polar unsaturated substrates such as aldehydes, ketones, enones, nitroarenes and N-heteroaromatics. Without an N-H group on the catalyst, the chemoselectivity was controlled precisely by the reaction temperature. The catalytic efficiency, chemoselectivity and robustness of this Fe/P4N2 catalyst found its merit in the preparation of several important drug intermediates. A diamagnetic trans-iron dihydride complex, formed under the reaction conditions, was supposed to be an on-cycle catalytically active species.<br>

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A High Resolution Study of Alumina Supported Iridium Catalysts

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s1431927600000878 ◽

1980 ◽

Vol 38 ◽

pp. 202-203

Author(s):

C. Stoeckert ◽

B. Etherton ◽

M. Beer ◽

J. Gryder

Keyword(s):

Electron Microscope ◽

High Resolution ◽

Metal Particles ◽

Optical Transfer Function ◽

Particle Sizes ◽

Iridium Catalysts ◽

Transmission Electron ◽

Optical Transfer ◽

Conventional Transmission Electron Microscope ◽

Resolution Study

The interpretation of the activity of catalysts requires information about the sizes of the metal particles, since this has implications for the number of surface atoms available for reaction. To determine the particle dimensions we used a high resolution STEM1. Such an instrument with its simple optical transfer function is far more suitable than a conventional transmission electron microscope for the establishment of particle sizes. We report here our study on the size and number distribution of Ir particles supported on Al2O3 and also examine simple geometric models for the shape of Ir particles.

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