Friday, April 7, 2017

Iron-Catalyzed C−H Bond Activation

Iron-Catalyzed C−H Bond Activation

Shang, R.; Ilies, L.; Nakamura, E.
University of Tokyo

Chem. Rev. ASAP (http://pubs.acs.org/doi/pdf/10.1021/acs.chemrev.6b00772)
DOI: 10.1021/acs.chemrev.6b00772

Abstract:
Catalytic C−H bond activation, which was an elusive subject of chemicalresearch until the 1990s, has now become a standard synthetic method for the formation of new C−C and C−heteroatom bonds. The synthetic potential of C−H activation was first described for ruthenium catalysis and is now widely exploited by the use of various precious metals. Driven by the increasing interest in chemical utilization of ubiquitous metals that are abundant and nontoxic, iron catalysis has become a rapidly growing area of research, and iron-catalyzed C−H activation has been most actively explored in recent years. In this review, we summarize the development of stoichiometric C−H activation, which has a long history, and catalytic C−H functionalization, which emerged about 10 years ago. We focus in this review on reactions that take place via reactive organoiron intermediates, and we excluded those that use iron as a Lewis acid or radical initiator. The contents of this review are categorized by the type of C−H bond cleaved and the type of bond formed thereafter, and it covers the reactions of simple substrates and substrates possessing a directing group that anchors the catalyst to the substrate, providing an overview of iron-mediated and iron-catalyzed C−H activation reported in the literature by October 2016.

TOC:

Thursday, April 6, 2017

Copper-Catalyzed Remote C–H Functionalizations of Naphthylamides through a Coordinating Activation Strategy and Single-Electron-Transfer (SET) Mechanism

 http://pubs.acs.org/doi/abs/10.1021/acscatal.6b03671

Copper-Catalyzed Remote C–H Functionalizations of Naphthylamides through a Coordinating Activation Strategy and Single-Electron-Transfer (SET) Mechanism

Jun-Ming Li, Yong-Heng Wang, Yang Yu, Rui-Bo Wu, Jiang Weng*, and Gui Lu*
Institute of Medicinal Chemistry, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou 510006, People’s Republic of China
ACS Catal., 2017, 7, pp 2661–2667
DOI: 10.1021/acscatal.6b03671
Publication Date (Web): February 27, 2017
Copyright © 2017 American Chemical Society

Abstract

Achieving p-CAr–H site selectivity is one of the major challenges in direct carbon–hydrogen (C–H) functionalization reactions. Herein, the copper-catalyzed and picolinamide-assisted remote p-C–H sulfonylation of 1-naphthylamides was realized. The synthetic utility of this method was further examined by sequential functionalizations and the efficient synthesis of the pharmaceutically useful 5-HT6 serotonin receptor ligand. This approach also provided a general strategy for other p-C–H bond functionalization, such as highly selective constructions of C–O, C–Br, C–I, C–C, and C–N bonds. Control experiments and theoretical calculations suggested that this C–H sulfonylation reaction might proceed through a single-electron-transfer process.

Tuesday, April 4, 2017

Platinum(II)-Crosslinked Single-Chain Nanoparticles: An Approach towards Recyclable Homogeneous Catalysts

Platinum(II)-Crosslinked Single-Chain Nanoparticles: An Approach towards Recyclable Homogeneous Catalysts
 
 Knoefl, N. D.; Rothfuss, H.; Willenbacher, J.; Barner-Kowollik, C.; Roesky, P. W. 

Karlsruhe Institute for Technology; UC Santa Barbara
 
Angew. Chem. ASAP
http://onlinelibrary.wiley.com/doi/10.1002/anie.201700718/epdf


Abstract: 
 
 We introduce the synthesis and in-depth characterization of platinum(II)-crosslinked single-chain nanoparticles (PtII-SCNPs) to demonstrate their application as a recyclable homogeneous catalyst. Specifically, a linear precursor copolymer of styrene and 4-(diphenylphosphino)styrene was synthesized via nitroxide-mediated polymerization. The triarylphosphine ligand moieties along the backbone allowed for the intramolecular crosslinking of single chains via the addition of [Pt(1,5-cyclooctadiene)Cl2] in dilute solution. The successful formation of well-defined PtII-SCNPs was evidenced by size exclusion chromatography, dynamic light scattering, nuclear magnetic resonance (1H,31P{1H},195Pt), and diffusion-ordered spectroscopy. Finally, the activity of the PtII-SCNPs as homogeneous, yet recyclable catalyst was successfully demonstrated using the example of the amination of allyl alcohol.