Many recent studies have used KOtBu in organic reactions that involve single electron transfer; in the literature, the electron transfer is proposed to occur either directly from the metal alkoxide or indirectly, following reaction of the alkoxide with a solvent or additive. These reaction classes include coupling reactions of halobenzenes and arenes, reductive cleavages of dithianes and SRN1 reactions.
What is the role of KOtBu in organic reactions?
abstract = "Many recent studies have used KOtBu in organic reactions that involve single electron transfer; in the literature, the electron transfer is proposed to occur either directly from the metal alkoxide or indirectly, following reaction of the alkoxide with a solvent or additive.
Where can I read about the chemistry of KOtBu?
You can read about the chemistry of KOtBu and more than 80 other reagents in undergraduate organic chemistry in the “Organic Chemistry Reagent Guide”, available here as a downloadable PDF. The Reagents App is also available for iPhone, click on the icon below! The original paper by W. Hofmann on a new method for olefin synthesis.
What is potassium tert-butoxide (KOt-Bu)?
Today’s reagent, potassium tert-butoxide (KOt-Bu), is a strong base just like all alkoxides, but there’s something about it that makes it special. If you’ve come across the tert-butyl group before, you should be able to remember one main thing: it’s really darn fat (although in these more sensitive times, “bulky” is the preferred nomenclature).
Why is t-BuOK used in condensation reactions?
Many condensation reactions (Stobe's, Darzen's) are seen to have greater yield when t-BuOK is used. Show activity on this post. Generally, it's just because there's a big bottle of t - B u O K lying around, so why bother using something else?
What is KOtBu used for?
Many recent studies have used KOtBu in organic reactions that involve single electron transfer; in the literature, the electron transfer is proposed to occur either directly from the metal alkoxide or indirectly, following reaction of the alkoxide with a solvent or additive.
Is KOtBu a strong base?
There are also some bases out there that are strong, NON-nucleophilic bases because they are very sterically hindered. An example of a base like this is KOtBu. The anion of tert-butyl alcohol is a huge base.
What does potassium t butoxide do?
Potassium tert-butoxide catalyzes the reaction of hydrosilanes and heterocyclic compounds to give the silyl derivatives, with release of H2.
What does sodium tert-butoxide do?
Sodium tert-butoxide is used to prepare tert-butoxide complexes.
What does naoch3 do in organic chemistry?
Sodium methoxide is a routinely used base in organic chemistry, applicable to the synthesis of numerous compounds ranging from pharmaceuticals to agrichemicals. As a base, it is employed in dehydrohalogenations and various condensations. It is also a nucleophile for the production of methyl ethers.
Is T butoxide a bulky base?
The base in this instance – potassium t-butoxide – is an extremely bulky base, and the proton we remove to form the Zaitsev product is on a tertiary carbon. As the oxygen from the base draws nearer to this proton, a steric clash occurs.
Is tert-butoxide a strong nucleophile?
Illustrated Glossary of Organic Chemistry - Tert-butoxide. Tert-butoxide (tert-butoxide ion; tBuO-): (CH3)3CO-; the conjugate base of tert-butanol. A strong base (frequently used in E2 and enolate reactions) but a fairly poor nucleophile due to steric hindrance.
What is T BuOK organic chemistry?
Potassium tert-butoxide (tBuOK) is traditionally used as a strong and non-nucleophilic base in organic synthesis. In recent years, tBuOK has seen widespread use in transition-metal-free reactions.
Is T BuOK a strong nucleophile?
t-BuOK is especially known as a strong base, and a poor nucleophile. Its large, bulky structure causes it to perform exceptionally poorly in substitution, literally eliminating any side reactions when the desired product is the elimination product.
Is sodium tert-butoxide a strong base?
Sodium tert-butoxide is used as a strong base and a non-nucleophilic base.
When sodium tert-butoxide and methyl iodide are heated the product formed is?
Answer. Answer: When potassium tert-butoxide and methyl bromide are heated, the product formed is. Isobutylene.
Can tert-butoxide do E1?
Tert-butoxide: if tBuO- is present in solution, SN1/E1 can't occur! The reaction will proceed through SN2 or E2 depending on the substrate.
What is the formula for potassium tert-butoxide?
Potassium tert-butoxide is the chemical compound with the formula K + (CH 3) 3 CO −. This colourless solid is a strong base (pKa of conjugate acid around 17), which is useful in organic synthesis. It exists as a tetrameric cubane-type cluster. It is often seen written in chemical literature as potassium t -butoxide.
Is potassium t-butoxide a solid?
Potassium t -but oxide is commercially available as a solution and as a solid, but it is often generated in situ for laboratory use because samples are so sensitive and older samples are often of poor quality. It is prepared by the reaction of dry tert -butyl alcohol with potassium metal. The solid is obtained by evaporating these solutions followed ...
Is tert butoxide a base?
The tert -butoxide species is itself useful as a strong, non-nucleophilic base in organic chemistry. It is not as strong as amide bases, e.g. lithium diisopropylamide, but stronger than potassium hydroxide.
Can potassium tert butoxide be added to dichloromethane?
Potassium tert -butoxide should never be added to dichloromethane. As a base, potassium tert-butoxide can extract a beta-proton and form the Hofmann product via an elimination reaction. This reaction has a high synthetic value as it can set up further reactions of the resultant alkene, especially regiochemical reactions.
Abstract
Many recent studies have used KOtBu in organic reactions that involve single electron transfer; in the literature, the electron transfer is proposed to occur either directly from the metal alkoxide or indirectly, following reaction of the alkoxide with a solvent or additive.
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Abstract
Long-standing controversial reports of electron transfer from KOtBu to benzophenone have been investigated and resolved.
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Dive into the research topics of 'Electron transfer reactions: KOtBu (but not NaOtBu) photoreduces benzophenone under activation by visible light'. Together they form a unique fingerprint.
Overview
Applications
The tert-butoxide species is itself useful as a strong, non-nucleophilic base in organic chemistry. It is not as strong as amide bases, e.g. lithium diisopropylamide, but stronger than potassium hydroxide. Its steric bulk inhibits the group from participating in nucleophilic addition, such as in a Williamson ether synthesis or an SN2 reaction. Substrates that are deprotonated by potassium t-butoxide include terminal acetylenes and active methylene compounds. It is useful in dehydrohal…
Preparation
Potassium t-butoxide is commercially available as a solution and as a solid, but it is often generated in situ for laboratory use because samples are so sensitive and older samples are often of poor quality. It is prepared by the reaction of dry tert-butyl alcohol with potassium metal. The solid is obtained by evaporating these solutions followed by heating the solid. The solid can be purified by sublimation at 220 °C and 1 mmHg. Sublimation can also take place at 140 °C and 0.…
Structure
Potassium tert-butoxide crystallises from tetrahydrofuran/pentane at −20 °C as [tBuOK·tBuOH]∞, which consists of infinite one-dimensional chains linked by hydrogen bonding. Sublimation of [tBuOK·tBuOH]∞ affords the tetramer [tBuOK]4, which adopts a cubane-like structure. Mild Lewis basic solvents such as THF and diethyl ether do not break up the tetrameric structure, which persists in the solid, in solution and even in the gas phase.
Modifications
Many modifications have been reported that influence the reactivity of this reagent. The compound adopts a complex cluster structure (the adjacent picture is a simplified cartoon), and additives that modify the cluster affect the reactivity of the reagent. For example, DMF, DMSO, hexamethylphosphoramide (HMPA), and 18-crown-6 interact with the potassium center, enhancing the basicity of the butoxide. Schlosser's base, a mixture of the alkoxide and an alkyl lithium comp…
Reactions
Potassium tert-butoxide reacts with chloroform yielding dichlorocarbene, the reaction can result in ignition. Potassium tert-butoxide should never be added to dichloromethane, as the reaction of 1,5g of potassium tert-butoxide with drops of dichloromethane can result in ignition over 2min.
As a base, potassium tert-butoxide can extract a beta-proton and form the Hofmann product via an elimination reaction. This reaction has a high synthetic value as it can set up further reaction…
Related compounds
• Sodium tert-butoxide
• Lithium tert-butoxide