scholarly journals A Giese Reaction for Electron-Rich Alkenes

2020 ◽  
Author(s):  
Qi Huang ◽  
Sankar Rao Suravarapu ◽  
Philippe Renaud
Keyword(s):  
Hydrogen Atom ◽  
Room Temperature ◽  
Chain Transfer ◽  
Chain Process ◽  
Enol Ethers ◽  
Silyl Enol Ethers ◽  
Terminal Alkenes ◽  
Enol Esters ◽  
A Chain ◽  
General Method

A general method for the hydroalkylation of electron-rich terminal and non-terminal alkenes such as enol esters, alkenyl sulfides, enol ethers, silyl enol ethers, enamides and enecarbamates has been developed. The reactions are carried out at room temperature under air initiation in the presence of triethylborane acting as a chain transfer reagent and 4-<i>tert</i>-butylcatechol (TBC) as a source of hydrogen atom. The efficacy of the reaction is best explained by very favorable polar effects supporting the chain process and minimizing undesired polar reactions. The stereoselective hydroalkylation of chiral <i>N</i>-(alk-1-en-1-yl)oxazolidin-2-ones takes place with good to excellent diastereocontrol.

scholarly journals A Giese Reaction for Electron-Rich Alkenes

2020 ◽  
Author(s):  
Qi Huang ◽  
Sankar Rao Suravarapu ◽  
Philippe Renaud
Keyword(s):  
Hydrogen Atom ◽  
Room Temperature ◽  
Chain Transfer ◽  
Chain Process ◽  
Enol Ethers ◽  
Silyl Enol Ethers ◽  
Terminal Alkenes ◽  
Enol Esters ◽  
A Chain ◽  
General Method

A general method for the hydroalkylation of electron-rich terminal and non-terminal alkenes such as enol esters, alkenyl sulfides, enol ethers, silyl enol ethers, enamides and enecarbamates has been developed. The reactions are carried out at room temperature under air initiation in the presence of triethylborane acting as a chain transfer reagent and 4-<i>tert</i>-butylcatechol (TBC) as a source of hydrogen atom. The efficacy of the reaction is best explained by very favorable polar effects supporting the chain process and minimizing undesired polar reactions. The stereoselective hydroalkylation of chiral <i>N</i>-(alk-1-en-1-yl)oxazolidin-2-ones takes place with good to excellent diastereocontrol.

Epoxidation of silyl enol ethers, phthalides, and enol esters by dimethyldioxirane

1989 ◽  
Vol 30 (47) ◽  
pp. 6497-6500 ◽  
Author(s):  
Waldemar Adam ◽  
Lazaros Hadjiarapoglou ◽  
Xiaoheng Wang
Keyword(s):  
Enol Ethers ◽  
Silyl Enol Ethers ◽  
Enol Esters

scholarly journals 2-Iodoxybenzoic Acid: An Oxidant for Functional Group Transformations: (A-Review)

2020 ◽  
Vol 36 (05) ◽  
pp. 792-803
Author(s):  
Vipin A. Nair
Keyword(s):  
Carbonyl Compounds ◽  
Room Temperature ◽  
Water Soluble ◽  
Enol Ethers ◽  
Silyl Enol Ethers ◽  
Carbon Carbon Bond ◽  
Oxidation Of Alcohols ◽  
Major Application ◽  
Almost All ◽  
Derivatives Of

A major application of 2-Iodoxybenzoic acid (IBX) is the oxidation of alcohols to carbonyl compounds, at room temperature. IBX is insoluble in almost all solvents, except DMSO. IBX tolerates amine functionality and is therefore used for the oxidation of amino alcohols to amino carbonyl compounds. IBX oxidizes 1,2-glycols without the cleavage of the glycol carbon-carbon bond. Allylic and benzylic positions are also susceptible to oxidation by IBX. Synthesis of a,b-unsaturated carbonyl compounds from carbonyl compounds can be accomplished by using IBX as oxidant. Silyl enol ethers undergo oxidation upon exposure to IBX and 4-methoxypyridine N-oxide. Water-soluble derivatives of IBX, and polymer-based IBX, with additional advantages, have also been developed. IBX mediated transformations facilitate the construction of diverse heterocyclic systems.

Addition of Allylsilanes and Silyl Enol Ethers to Small Oxygenated Rings: New Tools for Organic Synthesis

2014 ◽  
Vol 18 (5) ◽  
pp. 525-546 ◽  
Author(s):  
Carmen Hernandez-Cervantes ◽  
Miriam Alvarez-Corral ◽  
Manuel Munoz-Dorado ◽  
Ignacio Rodriguez-Garcia
Keyword(s):  
Organic Synthesis ◽  
Enol Ethers ◽  
Silyl Enol Ethers

scholarly journals Lithium-mediated Ferration of Fluoroarenes

2020 ◽  
Vol 74 (11) ◽  
pp. 866-870
Author(s):  
Lewis C. H. Maddock ◽  
Alan Kennedy ◽  
Eva Hevia
Keyword(s):  
Hydrogen Atom ◽  
Organometallic Chemistry ◽  
Room Temperature ◽  
Structural Elucidation ◽  
Side Reactions ◽  
Metal Base ◽  
Lithium Amide ◽  
Mixed Metal ◽  
Important Challenge

While fluoroaryl fragments are ubiquitous in many pharmaceuticals, the deprotonation of fluoroarenes using organolithium bases constitutes an important challenge in polar organometallic chemistry. This has been widely attributed to the low stability of the in situ generated aryl lithium intermediates that even at –78 °C can undergo unwanted side reactions. Herein, pairing lithium amide LiHMDS (HMDS = N{SiMe3}2) with FeII(HMDS)2 enables the selective deprotonation at room temperature of pentafluorobenzene and 1,3,5-trifluorobenzene via the mixed-metal base [(dioxane)LiFe(HMDS)3] (1) (dioxane = 1,4-dioxane). Structural elucidation of the organometallic intermediates [(dioxane)Li(HMDS)2Fe(ArF)] (ArF = C6F5, 2; 1,3,5-F3-C6H2, 3) prior electrophilic interception demonstrates that these deprotonations are actually ferrations, with Fe occupying the position previously filled by a hydrogen atom. Notwithstanding, the presence of lithium is essential for the reactions to take place as Fe II (HMDS)2 on its own is completely inert towards the metallation of these substrates. Interestingly 2 and 3 are thermally stable and they do not undergo benzyne formation via LiF elimination.

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