A new strategy for designing non-C2-symmetric monometallic bifunctional catalysts and their application in enantioselective cyanation of aldehydes

Chemistry : a European Journal
Fei YangJingsong You

Abstract

A monometallic bifunctional catalyst, in which only one imidazolyl moiety is directly attached at the 3-position of a binaphthol moiety, has been developed. The ligand (R)-1, which lacks C2-symmetry and flexible linkers, in combination with Ti(OiPr)4, has been demonstrated to promote the enantioselective cyanation of aldehydes with trimethylsilylcyanide (TMSCN), giving excellent enantioselectivities of up to 98 % ee and high yields of up to 99 %. The use of this bifunctional catalytic system obviates the need for additives and is extremely simple as the reagents are added in one portion at the beginning of the reaction. The protocol has been found to tolerate a relatively wide range of aldehydes when 10 mol % of the (R)-1/Ti(OiPr)4 complex is deployed in CH2Cl2 at -40 degrees C, the conditions which proved most practical and effective. The asymmetric cyanations also proceeded with lower catalyst loadings (5 mol %, or even 2 mol %), still giving satisfactory enantiomeric excesses and yields. Interestingly, the use of freshly distilled TMSCN dried over CaH2 gave a low enantioselectivity and only a moderate yield of the adduct as compared with direct use of the commercial reagent. The results of 13C NMR spectroscopic studies impli...Continue Reading

References

Aug 1, 1978·Angewandte Chemie·F Schneider
Jun 13, 2002·Chemical Reviews·Masakatsu Shibasaki, Naoki Yoshikawa
Oct 3, 2002·Chemical Communications : Chem Comm·Masakatsu ShibasakiKen Funabashi
Aug 14, 2003·Chemical Reviews·Yu ChenAndrei K Yudin
Jan 23, 2004·Chemical Communications : Chem Comm·Jing-Bo LanRu-Gang Xie
May 20, 2004·Angewandte Chemie·Jean-Michel Brunel, Ian P Holmes
Jun 4, 2004·Journal of the American Chemical Society·Matthew B FiermanScott J Miller
Mar 10, 2005·Chemical Reviews·Jean Michel Brunel
Mar 17, 2005·Angewandte Chemie·Hisashi Yamamoto, Kentaro Futatsugi
Mar 19, 2005·Chemistry : a European Journal·Alejandro BaezaJosé M Saá
Aug 9, 2005·Chemistry : a European Journal·Douglas B Grotjahn
Dec 21, 2006·Journal of the American Chemical Society·Chad A LewisScott J Miller
Apr 24, 2007·Angewandte Chemie·Naoto UtsumiCarlos F Barbas

❮ Previous
Next ❯

Citations

Jun 25, 2010·Chemical Communications : Chem Comm·Yoshifumi SakaiTsutomu Katsuki
Apr 17, 2013·Chemistry : a European Journal·Azusa KondohAlois Fürstner
May 16, 2020·Natural Product Reports·Ryan M Friedrich, Gregory K Friestad
Dec 11, 2008·Chemical Reviews·Michael NorthCarl Young
Sep 9, 2010·The Journal of Organic Chemistry·Kai LangSukwon Hong

❮ Previous
Next ❯

Related Concepts

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.