Cascade Michael Addition/Cycloketalization of Cyclic 1,3-Dicarbonyl Compounds: Important Role of the Tethered Alcohol of α,β-Unsaturated Carbonyl Compounds on Reaction Rate and Regioselectivity

2014 ◽  
Vol 79 (18) ◽  
pp. 8774-8785 ◽  
Author(s):  
Hongliang Yao ◽  
Liyan Song ◽  
Yuan Liu ◽  
Rongbiao Tong
Keyword(s):  
Michael Addition ◽  
Carbonyl Compounds ◽  
Reaction Rate ◽  
Dicarbonyl Compounds

Qualitative LC-MS/MS identification, formation, and stability of adducts and cross-links arising from the reactions of glutathione with the model enal systems

2021 ◽  
Vol 25 ◽  
Author(s):  
Kinga Salus ◽  
Donata Pluskota-Karwatka
Keyword(s):  
Lipid Peroxidation ◽  
Michael Addition ◽  
Carbonyl Compounds ◽  
Cross Linking ◽  
Amino Group ◽  
Cross Links ◽  
Enzymatic Detoxification

: Glutathione (GSH), due to the ability to capture the reactive electrophiles of exo- and endogenous origin, is expected to prevent cross-linking induced by these compounds. However, it may instead become cross-linked itself. We subjected glutathione to reactions with model α,β-unsaturated carbonyl systems resulting from the interactions of adenosine with bifunctional aldehyde products of lipid peroxidation, and identified a range of adducts and cross-linked products. We found that the S-conjugated adducts, initially formed in the typical for GSH Michael addition to α,β-unsaturated carbonyl system, unexpectedly undergo gradual degradation giving rise to the final N-conjugated products, in which formation of the peptide amino group was involved instead of the sulfhydryl functionality. This finding shows that the role of the GSH amino group in the non-enzymatic detoxification is underestimated and that reactions between cellular α,β-unsaturated carbonyl compounds, and GSH may be more complex than are presently perceived.

scholarly journals Robust and efficient hydrogenation of carbonyl compounds catalysed by mixed donor Mn(I) pincer complexes

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Wenjun Yang ◽  
Ivan Yu. Chernyshov ◽  
Robin K. A. van Schendel ◽  
Manuela Weber ◽  
Christian Müller ◽  
...  
Keyword(s):  
Noble Metal ◽  
Crucial Role ◽  
Carbonyl Compounds ◽  
Catalytic Performance ◽  
Hydrogen Atmosphere ◽  
Pincer Complexes ◽  
Catalyst Activation ◽  
Hydrogenation Catalysts ◽  
Induction Times

AbstractAny catalyst should be efficient and stable to be implemented in practice. This requirement is particularly valid for manganese hydrogenation catalysts. While representing a more sustainable alternative to conventional noble metal-based systems, manganese hydrogenation catalysts are prone to degrade under catalytic conditions once operation temperatures are high. Herein, we report a highly efficient Mn(I)-CNP pre-catalyst which gives rise to the excellent productivity (TOF° up to 41 000 h−1) and stability (TON up to 200 000) in hydrogenation catalysis. This system enables near-quantitative hydrogenation of ketones, imines, aldehydes and formate esters at the catalyst loadings as low as 5–200 p.p.m. Our analysis points to the crucial role of the catalyst activation step for the catalytic performance and stability of the system. While conventional activation employing alkoxide bases can ultimately provide catalytically competent species under hydrogen atmosphere, activation of Mn(I) pre-catalyst with hydride donor promoters, e.g. KHBEt3, dramatically improves catalytic performance of the system and eliminates induction times associated with slow catalyst activation.

scholarly journals Central role of carbonyl compounds in atmospheric chemistry

2000 ◽  
Vol 105 (D15) ◽  
pp. 19771-19778 ◽  
Author(s):  
D. J. Lary ◽  
D. E. Shallcross
Keyword(s):  
Atmospheric Chemistry ◽  
Carbonyl Compounds
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