A Versatile New Catalyst for the Enantioselective Isomerization of Allylic Alcohols to Aldehydes:  Scope and Mechanistic Studies

2001 ◽  
Vol 66 (24) ◽  
pp. 8177-8186 ◽  
Author(s):  
Ken Tanaka ◽  
Gregory C. Fu
Keyword(s):  
Allylic Alcohols ◽  
Mechanistic Studies

From Allylic Alcohols to Aldols through a New Nickel-Mediated Tandem Reaction: Synthetic and Mechanistic Studies

2006 ◽  
Vol 12 (12) ◽  
pp. 3261-3274 ◽  
Author(s):  
David Cuperly ◽  
Julien Petrignet ◽  
Christophe Crévisy ◽  
René Grée
Keyword(s):  
Tandem Reaction ◽  
Allylic Alcohols ◽  
Mechanistic Studies

Temporal and mechanistic studies on the resistance of glioma cells to temozolomide

2016 ◽  
Vol 228 (06/07) ◽  
Author(s):  
WP Roos ◽  
M Eich ◽  
S Quiros ◽  
AV Knizhnik ◽  
T Nikolova ◽  
...  
Keyword(s):  
Glioma Cells ◽  
Mechanistic Studies

Active MnO2 As a Mild Oxidizing Reagent for the Controlled Oxidation of Benzylic and Allylic Alcohols

2012 ◽  
Vol 2 (6) ◽  
pp. 48-48
Author(s):  
Y. M. Nandurkar Y. M. Nandurkar ◽  
◽  
B. B. Bahule B. B. Bahule
Keyword(s):  
Allylic Alcohols

Bringing Biocatalysis into the Deuteration Toolbox

2019 ◽  
Author(s):  
Jack Rowbotham ◽  
Oliver Lenz ◽  
Holly Reeve ◽  
Kylie Vincent
Keyword(s):  
Late Stage ◽  
Hydrogen Isotope ◽  
Reductive Amination ◽  
Mechanistic Studies ◽  
Ambient Conditions ◽  
Synthetic Pathway ◽  
Drug Candidates ◽  
Isotopic Selectivity ◽  
Reducing Equivalents

<p></p><p>Chemicals labelled with the heavy hydrogen isotope deuterium (<sup>2</sup>H) have long been used in chemical and biochemical mechanistic studies, spectroscopy, and as analytical tracers. More recently, demonstration of selectively deuterated drug candidates that exhibit advantageous pharmacological traits has spurred innovations in metal-catalysed <sup>2</sup>H insertion at targeted sites, but asymmetric deuteration remains a key challenge. Here we demonstrate an easy-to-implement biocatalytic deuteration strategy, achieving high chemo-, enantio- and isotopic selectivity, requiring only <sup>2</sup>H<sub>2</sub>O (D<sub>2</sub>O) and unlabelled dihydrogen under ambient conditions. The vast library of enzymes established for NADH-dependent C=O, C=C, and C=N bond reductions have yet to appear in the toolbox of commonly employed <sup>2</sup>H-labelling techniques due to requirements for suitable deuterated reducing equivalents. By facilitating transfer of deuterium atoms from <sup>2</sup>H<sub>2</sub>O solvent to NAD<sup>+</sup>, with H<sub>2</sub> gas as a clean reductant, we open up biocatalysis for asymmetric reductive deuteration as part of a synthetic pathway or in late stage functionalisation. We demonstrate enantioselective deuteration via ketone and alkene reductions and reductive amination, as well as exquisite chemo-control for deuteration of compounds with multiple unsaturated sites.</p><p></p>

Mechanistic Study and Development of Catalytic Reactions of Sm(II)

2018 ◽  
Author(s):  
Sandepan Maity ◽  
Robert Flowers
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Proton Donor ◽  
Catalytic Reactions ◽  
Mechanistic Study ◽  
Mechanistic Studies ◽  
Cyclization Reactions ◽  
Mechanistic Approach ◽  
Donor Source

Despite the broad utility and application of SmI<sub>2</sub>in synthesis, the reagent is used in stoichiometric amounts and has a high molecular weight, resulting in a large amount of material being used for reactions requiring one or more equivalents of electrons. We report mechanistic studies on catalytic reactions of Sm(II) employing a terminal magnesium reductant and trimethyl silyl chloride in concert with a non-coordinating proton donor source. Reactions using this approach permitted reductions with as little as 1 mol% Sm. The mechanistic approach enabled catalysis employing HMPA as a ligand, facilitating the development of catalytic Sm(II) 5-<i>exo</i>-<i>trig </i>ketyl olefin cyclization reactions.

Bimetallic Radical Redox-Relay Catalysis for the Isomerization of Epoxides to Allylic Alcohols

2019 ◽  
Author(s):  
Ke-Yin Ye ◽  
Terry McCallum ◽  
Song Lin
Keyword(s):  
Ring Opening ◽  
High Reactivity ◽  
Hydrogen Atom Transfer ◽  
Organic Radicals ◽  
Epoxide Ring ◽  
Allylic Alcohols ◽  
Epoxide Ring Opening ◽  
Bond Forming ◽  
Co Catalysts ◽  
The Rich

Organic radicals are generally short-lived intermediates with exceptionally high reactivity. Strategically, achieving synthetically useful transformations mediated by organic radicals requires both efficient initiation and selective termination events. Here, we report a new catalytic strategy, namely bimetallic radical redox-relay, in the regio- and stereoselective rearrangement of epoxides to allylic alcohols. This approach exploits the rich redox chemistry of Ti and Co complexes and merges reductive epoxide ring opening (initiation) with hydrogen atom transfer (termination). Critically, upon effecting key bond-forming and -breaking events, Ti and Co catalysts undergo proton-transfer/electron-transfer with one another to achieve turnover, thus constituting a truly synergistic dual catalytic system.<br>

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