Selective C–H Activation by Ruthenium(II) Carboxylate and Nickelaelectro-Catalysis
by Shoukun Zhang
Date of Examination:2021-01-11
Date of issue:2021-01-28
Advisor:Prof. Dr. Lutz Ackermann
Referee:Prof. Dr. Shoubhik Das
Referee:Prof. Dr. Manuel Alcarazo
Referee:Prof. Dr. Dietmar Stalke
Referee:Prof. Dr. Johannes C. L. Walker
Referee:Dr. Michael John
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Description:meta- or ortho- C–H Activation by Ruthenium(II) Carboxylate; Nickelaelectro-Catalyzed C-H amination, secondary alkoxylation, phosphorylation
Abstract
English
This doctoral thesis was divided into two main parts. In the first part, ruthenium(II)-catalyzed ortho-C–H alkynylations of diverse benzoic acids were achieved for the synthesis of aromatic alkynes. And meta-C–H activations, including mono- or difluoromethylation and alkylation through the σ-activation of the cyclometallated intermediate were also efficiently developed by ruthenium catalysis. In the second part, the first nickela-electrochemical C–H activation, including C–H amination, challenging secondary alkoxylation and phosphorylation in a dehydrogenative manner employing green and cheap electricity as the oxidant, providing an expedient approach to arylamines, aryl ethers and arylphosphonates. Detailed mechanistic studies including the isolation of catalytically relevant nickel(III) complex, cyclovoltammetry, and computation provided strong support for an oxidation-induced reductive elimination at nickel(III).
Keywords: meta-C–H difluomethylation or monofluomethylation; C–H Activation; C–H Amination; C–H Alkoxylation; C–H Phosphorylation; ortho-C–H alkynylation; Nickel; Ruthenium; Electrochemistry; Electrocatalysis