Synthesis 2021; 53(17): 2911-2946
DOI: 10.1055/a-1485-5156
special topic
Bond Activation – in Honor of Prof. Shinji Murai

Remote C–H Functionalizations by Ruthenium Catalysis

Authors


Generous support by the DAAD (fellowship to K.K.), the Alexander von Humboldt foundation (fellowship to R.C.S.) and the DFG (SPP1807 and Gottfried-Wilhelm-Leibniz award to L.A.) is gratefully acknowledged.


Graphical Abstract

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Dedicated to Prof. Shinji Murai

Abstract

Synthetic transformations of otherwise inert C–H bonds have emerged as a powerful tool for molecular modifications during the last decades, with broad applications towards pharmaceuticals, material sciences, and crop protection. Consistently, a key challenge in C–H activation chemistry is the full control of site-selectivity. In addition to substrate control through steric hindrance or kinetic acidity of C–H bonds, one important approach for the site-selective C–H transformation of arenes is the use of chelation-assistance through directing groups, therefore leading to proximity-induced ortho-C–H metalation. In contrast, more challenging remote C–H activations at the meta- or para-positions continue to be scarce. Within this review, we demonstrate the distinct character of ruthenium catalysis for remote C–H activations until March 2021, highlighting among others late-stage modifications of bio-relevant molecules. Moreover, we discuss important mechanistic insights by experiments and computation, illustrating the key importance of carboxylate-assisted C–H activation with ruthenium(II) complexes.

1 Introduction

2 Stoichiometric Remote C–H Functionalizations

3 meta-C–H Functionalizations

4 para-C–H Functionalizations

5 meta-/ortho-C–H Difunctionalizations

6 Conclusions



Publication History

Received: 24 March 2021

Accepted after revision: 19 April 2021

Accepted Manuscript online:
19 April 2021

Article published online:
20 May 2021

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