Olefins as steering ligands for homogeneously catalyzed hydrogenations

Chemistry : a European Journal
Pascal MaireHansjörg Grützmacher

Abstract

Iridium(I) complexes containing a (5H-dibenzo[a,d]cyclohepten-5-yl)-phosphane (tropp(R); R = phosphorus-bound substituent = Ph, Cyc) as a rigid, concave-shaped, mixed phosphane olefin ligand were prepared and tested as catalyst precursors in the hydrogenation of imines. With the complex [Ir(tropp(Cyc))(cod)]OTf, turnover frequencies (TOFs) of >6000 h(-1) were reached in the hydrogenation of N-phenyl-benzylidenamine, PhN==CHPh. Lower activities (TOF>80 h(-1)) are observed with N-phenyl-(1-phenylethylidene)amine, PhN==CMePh. Chiral tropp-type ligands were prepared in few simple steps. Monosubstitution of the olefinic unit in the dibenzo[a,d]cycloheptenyl moiety with (R)- or (S)-mentholate gave mixtures of diastereomers that could be separated and isolated in enantiomerically pure form. Iridium(I) complexes with these ligands are rare examples of side-on bonded enolether complexes. In catalytic imine hydrogenations, complete conversion (>98 %) was reached in all cases (conditions: p[H(2)] = 50 bar, T = 50 degrees C, t = 2 h, substrate/catalyst 100:1). The best enantiomeric excess (ee = 86 % S isomer) was reached with PhN==CMePh as substrate and the R,R form of the (10-menthyloxy-5H-dibenzo[a,d]cyclohepten-5-yl)diphenylphosphane li...Continue Reading

Citations

Apr 25, 1977·Biochimica Et Biophysica Acta·A BabaW W Fish
Jul 22, 2016·The Journal of Organic Chemistry·Qi ZhangYao Fu
May 18, 2016·Angewandte Chemie·Ernest SalomóXavier Verdaguer
Dec 16, 2004·Chemical Communications : Chem Comm·Torsten BüttnerHansjörg Grützmacher
Apr 14, 2016·Chemical Communications : Chem Comm·Demyan E ProkopchukHansjörg Grützmacher
May 9, 2015·Chemical Society Reviews·Gellért SiposReto Dorta
Nov 3, 2017·Yakugaku zasshi : Journal of the Pharmaceutical Society of Japan·Kazuteru Usui
May 24, 2006·Chemistry : a European Journal·Elisabetta PirasHansjörg Grützmacher
Jan 24, 2019·Organic & Biomolecular Chemistry·Takashi MinoMasami Sakamoto
Oct 24, 2007·Dalton Transactions : an International Journal of Inorganic Chemistry·Eduardo MolinosAndrew S Weller
Nov 10, 2007·Chemistry : a European Journal·Thomas M DouglasPrabha Vadivelu
Dec 18, 2007·Angewandte Chemie·Jeffrey B Johnson, Tomislav Rovis
May 7, 2008·Angewandte Chemie·Christian DefieberErick M Carreira
Oct 22, 2008·Chemical Communications : Chem Comm·Paul S Pregosin
Jun 15, 2010·Chemistry : a European Journal·Catalina FerrerXavier Verdaguer
Aug 10, 2006·Chemical Communications : Chem Comm·Thomas M DouglasAndrew S Weller
Mar 25, 2014·Chemical Communications : Chem Comm·Heng ZhangShang-Dong Yang
Feb 20, 2014·Chemical Communications : Chem Comm·Yi Li, Ming-Hua Xu
Jul 4, 2009·The Journal of Organic Chemistry·Neil CockburnWilliam Tam
Aug 21, 2009·Organic Letters·Tobias Minuth, Mike M K Boysen
Jan 10, 2009·Journal of the American Chemical Society·Guo-Hua HouQi-Lin Zhou
Aug 28, 2010·Journal of the American Chemical Society·Guohua HouXumu Zhang

❮ 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.