Enantioselective hydrogenation of alkenes with iridium-PHOX catalysts: a kinetic study of anion effects

Chemistry : a European Journal
Sebastian P SmidtAndreas Pfaltz

Abstract

In the asymmetric hydrogenation of unfunctionalized olefins with cationic iridium-PHOX catalysts, the reaction kinetics and, as a consequence, catalyst activity and productivity depend heavily on the counterion. A strong decrease in the reaction rate is observed in the series [Al[OC(CF3)3]4]- >BArF- >[B(C6F5)4]- >PF6- >BF4- >CF3SO3-. With the first two anions, high rates, turnover frequencies (TOF >5000 h(-1) at 4 degrees C), and turnover numbers (TONs) of 2000-5000 are routinely achieved. The hexafluorophosphate salt reacts with lower rates, although they are still respectable; however, this salt suffers from deactivation during the reaction and extreme water-sensitivity, especially at low catalyst loading. Triflate and tetrafluoroborate almost completely inhibit the catalyst. In contrast to the hexafluorophosphate salt, catalysts with [Al[OC(CF3)3]4]-, BArF-, and [B(C6F5)4]- as counterions do not lose activity during the reaction and remain active, even after all the substrate has been consumed. In addition they are much less sensitive to moisture and, in general, rigorous exclusion of water and oxygen is not necessary. A first-order rate dependence on the hydrogen pressure was determined for the BArF- and the PF6- salts. At ...Continue Reading

Citations

Jan 10, 2017·Journal of the American Chemical Society·Cristiana Margarita, Pher G Andersson
Dec 15, 2015·Angewandte Chemie·Markus MeureschJürgen Klankermayer
Dec 20, 2007·Chemical Communications : Chem Comm·Yingjian XuJohn M Brown
Mar 18, 2017·Chemical Communications : Chem Comm·Sebastian D PikeAdrian B Chaplin
Aug 26, 2015·Chemical Communications : Chem Comm·Kunru YuXiaoming Feng
Oct 16, 2013·Angewandte Chemie·Zhenhua JiaChao-Jun Li
May 2, 2007·Dalton Transactions : an International Journal of Inorganic Chemistry·Gemma L MoxhamAndrew S Weller
Jun 22, 2007·Chemistry : a European Journal·Jianguang ZhouKevin Burgess
Jul 13, 2005·Angewandte Chemie·Richard FrantzJérôme Lacour
Sep 16, 2005·Chemistry : a European Journal·Xiuhua CuiKevin Burgess
Oct 6, 2005·Chemical Communications : Chem Comm·Judy CipotMark Stradiotto
Nov 2, 2005·Magnetic Resonance in Chemistry : MRC·Ignacio Fernández, Paul S Pregosin
Nov 24, 2005·Chemistry : a European Journal·Klas KällströmPher G Andersson
Dec 20, 2005·Chemistry : a European Journal·Anna TrifonovaPher G Andersson
Nov 23, 2006·Dalton Transactions : an International Journal of Inorganic Chemistry·Gemma L MoxhamAndrew S Weller
Apr 23, 2013·Chemistry : a European Journal·Agnieszka BartoszewiczBelén Martín-Matute
Nov 13, 2019·Journal of Labelled Compounds & Radiopharmaceuticals·William J KerrLaura C Paterson
Jul 30, 2020·Chemistry : a European Journal·Marvin FresiaThomas Lindel
Feb 1, 2020·Nature Communications·Shuai YuanMingxin Chang
Aug 19, 2010·Chemical Communications : Chem Comm·Magnus Rueping, René M Koenigs
May 11, 2011·Chemical Communications : Chem Comm·David H Woodmansee, Andreas Pfaltz
Mar 12, 2010·Chemistry : a European Journal·Alejandro Baeza, Andreas Pfaltz
Nov 17, 2012·Chemistry : a European Journal·Xiao XiaoXiaoming Feng
Sep 11, 2014·Organic & Biomolecular Chemistry·Alan R KennedyMarc Reid
Feb 13, 2007·Chemistry : a European Journal·Adriano ZecchinaSilvia Bordiga
Mar 8, 2011·Chemistry : a European Journal·Axel Franzke, Andreas Pfaltz
Apr 22, 2009·Dalton Transactions : an International Journal of Inorganic Chemistry·Serin L DabbJörg Wagler

❮ Previous
Next ❯

Trending Feeds

COVID-19

Coronaviruses encompass a large family of viruses that cause the common cold as well as more serious diseases, such as the ongoing outbreak of coronavirus disease 2019 (COVID-19; formally known as 2019-nCoV). Coronaviruses can spread from animals to humans; symptoms include fever, cough, shortness of breath, and breathing difficulties; in more severe cases, infection can lead to death. This feed covers recent research on COVID-19.

Blastomycosis

Blastomycosis fungal infections spread through inhaling Blastomyces dermatitidis spores. Discover the latest research on blastomycosis fungal infections here.

Nuclear Pore Complex in ALS/FTD

Alterations in nucleocytoplasmic transport, controlled by the nuclear pore complex, may be involved in the pathomechanism underlying multiple neurodegenerative diseases including Amyotrophic Lateral Sclerosis and Frontotemporal Dementia. Here is the latest research on the nuclear pore complex in ALS and FTD.

Applications of Molecular Barcoding

The concept of molecular barcoding is that each original DNA or RNA molecule is attached to a unique sequence barcode. Sequence reads having different barcodes represent different original molecules, while sequence reads having the same barcode are results of PCR duplication from one original molecule. Discover the latest research on molecular barcoding here.

Chronic Fatigue Syndrome

Chronic fatigue syndrome is a disease characterized by unexplained disabling fatigue; the pathology of which is incompletely understood. Discover the latest research on chronic fatigue syndrome here.

Evolution of Pluripotency

Pluripotency refers to the ability of a cell to develop into three primary germ cell layers of the embryo. This feed focuses on the mechanisms that underlie the evolution of pluripotency. Here is the latest research.

Position Effect Variegation

Position Effect Variagation occurs when a gene is inactivated due to its positioning near heterochromatic regions within a chromosome. Discover the latest research on Position Effect Variagation here.

STING Receptor Agonists

Stimulator of IFN genes (STING) are a group of transmembrane proteins that are involved in the induction of type I interferon that is important in the innate immune response. The stimulation of STING has been an active area of research in the treatment of cancer and infectious diseases. Here is the latest research on STING receptor agonists.

Microbicide

Microbicides are products that can be applied to vaginal or rectal mucosal surfaces with the goal of preventing, or at least significantly reducing, the transmission of sexually transmitted infections. Here is the latest research on microbicides.