Remote Carboxylation with a Nickel Catalyst

 

 https://www.nature.com/nature/journal/v545/n7652/abs/nature22316.html

Remote carboxylation of halogenated aliphatic hydrocarbons with carbon dioxide

• Francisco Juliá-Hernández,
• Toni Moragas,
• Josep Cornella
• & Ruben Martin

Catalytic carbon–carbon bond formation has enabled the streamlining of synthetic routes when assembling complex molecules¹. It is particularly important when incorporating saturated hydrocarbons, which are common motifs in petrochemicals and biologically relevant molecules. However, cross-coupling methods that involve alkyl electrophiles result in catalytic bond formation only at specific and previously functionalized sites². Here we describe a catalytic method that is capable of promoting carboxylation reactions at remote and unfunctionalized aliphatic sites with carbon dioxide at atmospheric pressure. The reaction occurs via selective migration of the catalyst along the hydrocarbon side-chain³ with excellent regio- and chemoselectivity, representing a remarkable reactivity relay when compared with classical cross-coupling reactions. Our results demonstrate that site-selectivity can be switched and controlled, enabling the functionalization of less-reactive positions in the presence of a priori more reactive ones. Furthermore, we show that raw materials obtained in bulk from petroleum processing, such as alkanes and unrefined mixtures of olefins, can be used as substrates. This offers an opportunity to integrate a catalytic platform en route to valuable fatty acids by transforming petroleum-derived feedstocks directly⁴.

The Hitchhiker’s Guide to Flow Chemistry

The Hitchhiker’s Guide to Flow Chemistry

 Plutschack, M. B.; Pieber, B.; Gilmore, K.; Seeberger, P. H.

Max-Planck Institute of Colloids and Interfaces, Potsdam, Germany

Chem. Rev. ASAP
http://pubs.acs.org/doi/pdf/10.1021/acs.chemrev.7b00183

Abstract:

Flow chemistry involves the use of channels or tubing to conduct a reaction in a continuous stream rather than in a flask. Flow equipment provides chemists with unique control over reaction parameters enhancing reactivity or in some cases enabling new reactions. This relatively young technology has received a remarkable amount of attention in the past decade with many reports on what can be done in flow. Until recently, however, the question, “Should we do this in flow?” has merely been an afterthought. This review introduces readers to the basic principles and fundamentals of flow chemistry and critically discusses recent flow chemistry accounts.

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Olefin Hydroarylation Catalyzed by (pyridyl-indolate)Pt(II) Complexes: Catalytic Efficiencies and Mechanistic Aspects

Benjamin A. Suslick†‡ , Allegra L. Liberman-Martin†‡§, Truman C. Wambach†‡, and T. Don Tilley*†‡
† Department of Chemistry, University of California, Berkeley, California 94720, United States
‡ Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States

ACS Catal., 2017, 7, pp 4313–4322
DOI: 10.1021/acscatal.7b01560
Publication Date (Web): May 18, 2017

A series of Pt(II) complexes of the type (N–N)PtPh(SR2) (N–N = 2,2′-pyridyl-indolate) were prepared, and their performance as catalysts for the hydroarylation of olefins was assessed. Evidence that the catalysis is homogeneous and is Pt-mediated is provided by control experiments with added hindered base (2,6-di-tert-butyl-4-methylpyridine) and Hg(0). Two potential catalytic intermediates, (tBuPyInd)PtPh(C2H4) and (tBuPyInd)Pt(CH2CH2Ph)(C2H4), were synthesized, and their catalytic efficacy was explored. Additionally, decomposition and deactivation pathways, including styrene formation via β-hydride elimination and ligand reductive demetalation, were identified.

Iron-Catalyzed gem-Specific Dimerization of Terminal Alkynes

Liang, Qiuming, Kimberly M. Osten, and Datong Song. "Iron‐Catalyzed gem‐Specific Dimerization of Terminal Alkynes." Angewandte Chemie International Edition (2017).

DOI: 10.1002/anie.201700904

Abstract
We report a gem-specific homo- and cross-dimerization of terminal alkynes catalyzed by a well-defined iron(II) complex containing Cp* and picolyl N-heterocyclic carbene (NHC) ligands, and featuring a piano-stool structure. This catalytic system requires no additives and is compatible with a broad range of substrates, including those with polar functional groups such as NH and OH.