Enantioselective Protonation of Itaconimides with Thiols and the Rotational Kinetics of the Axially Chiral CN Bond

Lin, Shishi; Leow, Dasheng; Huang, Kuo‐Wei; Tan, Choon‐Hong

doi:10.1002/asia.200900331

Cited by 65 publications

(36 citation statements)

References 90 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Making use of C 2 ‐symmetric guanidine catalyst 54 (Scheme ), as a pro‐bifunctional guanidinium hydrogen‐bond donor entity, Tan and colleagues achieved tandem conjugate addition/protonation sequences between t BuSH ( 53 ) and sterically hindered N ‐aryl‐itaconimides 52 29. These useful cyclic 1,4‐dicarbonyl architectures also allow the exclusive formation of Z ‐enolate intermediates, avoiding the need for manipulation of a mixture of stereoisomers to be protonated.…”

Section: Asymmetric Protonation Of Catalytically Generated Carbanionsmentioning

confidence: 99%

Redox Non‐Innocence of Coordinated 2‐(Arylazo) Pyridines in Iridium Complexes: Characterization of Redox Series and an Insight into Voltage‐Induced Current Characteristics

Goswami

Sengupta

Paul

et al. 2014

Chemistry A European J

View full text Add to dashboard Cite

Two examples of a rare class of di-radical azo-anion complexes of 2-(arylazo) pyridine with Ir(III) carrier are introduced. Their electronic structures have been elucidated using a host of physical methods that include X-ray crystallography, cyclic voltammetry, electron paramagnetic resonance spectroscopy, and density functional theory. Room temperature magnetic moments of these are consistent with two nearly non-interacting azo-anion radicals. These displayed rich electrochemical properties consisting of six numbers of reversible and successive one electron CV-waves. Redox processes occur entirely at the coordinated ligands without affecting metal redox state. Apart from reporting their chemical characterization, I-V characteristics of these complexes in film state are investigated using sandwich-type devices comprising of a thin film of 100-125 nm thickness placed between two gold-plated ITO electrodes. These showed memory switching properties covering a useful voltage range with a reasonable ON/OFF ratio and also are suitable for RAM/ROM applications. I-V characteristics of two similar complexes of Rh and Cr with identical ligand environment and electronic structure are also referred for developing an insight into the memory switching ability of Ir- and Rh- complexes on the basis of comparative analysis of responses of the respective systems. In a nutshell, thorough analysis of voltage driven redox dynamics and corresponding solid and solution state current responses of all the systems are attempted and there from an unexplored class of switching devices are systematically introduced.

show abstract

Section: Asymmetric Protonation Of Catalytically Generated Carbanionsmentioning

confidence: 99%

Redox Non‐Innocence of Coordinated 2‐(Arylazo) Pyridines in Iridium Complexes: Characterization of Redox Series and an Insight into Voltage‐Induced Current Characteristics

Goswami

Sengupta

Paul

et al. 2014

Chemistry A European J

View full text Add to dashboard Cite

show abstract

“…56 From the Eyring plot, DH was +25.3 kcal·mol -1 and DS was -16.8 eu. The activation entropy indicated a more highly ordered transition state structure which was consistent with a bond rotation process.…”

Section: Scheme 27 Oxidation Of a Chiral Sulfide To Give A Sulfonementioning

confidence: 99%

Catalytic Reactions of Chiral Guanidines and Guanidinium Salts

Leow¹,

Tan²

2010

Synlett

Self Cite

View full text Add to dashboard Cite

show abstract

“…Ta na nd co-workers reported the bicyclic guanidine 34 b-catalyzed tandemc onjugate addition-enantioselectivep rotonation of N-aryl itaconimide 51 with thiol (Scheme 20). [34] Althoughc atalyst 34 b could control the newly created carbon stereocenter,t he N-Ar chiral axis could not be controlled, and product 52 was obtainedi na1:1d iastereomeric mixture.…”

Section: Axially Chiral Anilidesmentioning

confidence: 99%

Organocatalyzed Asymmetric Synthesis of Axially, Planar, and Helical Chiral Compounds

Shirakawa

Liu

Kaneko

2015

Chemistry An Asian Journal

101

View full text Add to dashboard Cite

Axially, planar, and helical chiral compounds are indispensable building blocks in modern organic synthesis. A wide variety of chiral ligands and catalysts were designed based on these chiral scaffolds, and these chiral ligands and catalysts were used for various catalytic asymmetric transformations to produce important chiral compounds in an optically enriched form. Furthermore, these chiral skeletons are found in the structure of biologically active natural products. Thus, the development of efficient enantioselective methods for the synthesis of these chiral compounds is an important task in the field of organic chemistry. In the last few years, organocatalyzed approaches, which are one of the most reliable catalytic asymmetric methods, became a hot topic. This Focus Review summarizes asymmetric organocatalytic methods for the synthesis of axially, planar, and helical chiral compounds as useful chiral building blocks.

show abstract

Enantioselective Protonation of Itaconimides with Thiols and the Rotational Kinetics of the Axially Chiral CN Bond

Cited by 65 publications

References 90 publications

Redox Non‐Innocence of Coordinated 2‐(Arylazo) Pyridines in Iridium Complexes: Characterization of Redox Series and an Insight into Voltage‐Induced Current Characteristics

Redox Non‐Innocence of Coordinated 2‐(Arylazo) Pyridines in Iridium Complexes: Characterization of Redox Series and an Insight into Voltage‐Induced Current Characteristics

Catalytic Reactions of Chiral Guanidines and Guanidinium Salts

Organocatalyzed Asymmetric Synthesis of Axially, Planar, and Helical Chiral Compounds

Contact Info

Product

Resources

About