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α-Amino Acid synthesis by C-C coupling - Organic …

On the other hand, it isreadily converted back to the precursor carbonyl compound by acid-catalyzedhydrolysis.

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Carboxylic acid - Synthesis of carboxylic acids | …

Thecatalyst, instead of being hydronium ion is the conjugate acid of the alcohol,since the reaction would be carried out in the alcohol as the solvent.

Video explaining Making Ethers - Williamson Ether Synthesis for Organic Chemistry

An enantioselective intramolecular chiral phosphoric acid-catalyzed cyclization of unsaturated acetals has been utilized for the synthesis of functionalized chiral piperidines. The chiral enol ether products of these cyclizations undergo subsequent in situ enantioenrichment through acetalization of the minor enantiomer. A new computational reaction exploration method was utilized to elucidate the mechanism and stereoselectivity of this transformation. Rather than confirming the originally postulated cyclization proceeding directly through a vinyl oxocarbenium ion, simulations identified an alternative two-step mechanism involving the formation of a mixed chiral phosphate acetal, which undergoes a concerted, asynchronous SN2′-like displacement to yield the product with stereoselectivity in agreement with experimental observations.

Acid catalyzed ether synthesis | scholarly search

Acid catalyzed ether synthesis…

AB - An enantioselective intramolecular chiral phosphoric acid-catalyzed cyclization of unsaturated acetals has been utilized for the synthesis of functionalized chiral piperidines. The chiral enol ether products of these cyclizations undergo subsequent in situ enantioenrichment through acetalization of the minor enantiomer. A new computational reaction exploration method was utilized to elucidate the mechanism and stereoselectivity of this transformation. Rather than confirming the originally postulated cyclization proceeding directly through a vinyl oxocarbenium ion, simulations identified an alternative two-step mechanism involving the formation of a mixed chiral phosphate acetal, which undergoes a concerted, asynchronous SN2′-like displacement to yield the product with stereoselectivity in agreement with experimental observations.

Because of its enhanced acidity, the hydrogen atom on the hydroxyl group is rather easily replaced by other substituents. A simple example is the facile reaction of simple alcohols with sodium (and sodium hydride), as described in the first equation below. Another such substitution reaction is the isotopic exchange that occurs on mixing an alcohol with deuterium oxide (heavy water). This exchange, which is catalyzed by acid or base, is very fast under normal conditions, since it is difficult to avoid traces of such catalysts in most experimental systems.

9.6: Williamson Ether Synthesis - Chemistry LibreTexts

Bronsted acid-catalyzed rapid enol-ether formation of 2-hydroxyindole-3-carboxaldehydes

The catalytic activity of various strong acid ion-exchange resins on the synthesis of methyl tert-butyl ether (MtBE) from methanol and isobutene has been investigated. Relative to Amberlyst 15, Kastel CS 381 and Amberlyst CSP have similar rate constants, whereas Duolite ES 276 and Amberlyst XE 307 have significantly higher and Duolite C26 and Duolite C16P substantially lower rate constants. All resins show a great decrease in catalytic activity if part of the protons is exchanged by sodium ions. At 10% proton capacity the rate constants per equivalent acid are reduced by a factor of 9 (for Amberlyst XE 307 and Kastel CS 381) to more than a factor 20 for Amberlyst 15 and Duolite ES 276, resulting in 100-200 times lower MtBE production rates. Depending on the catalyst applied, mass transfer limitations start to occur between 50 and 80 degrees C. Values of the effective diffusion coefficient of isobutene varied between 0.4 x 10(-9) and 4.1 x 10(-9) m(2) s(-1) at 80 degrees C.

Alkyl substitution of the hydroxyl group leads to ethers. This reaction provides examples of both strong electrophilic substitution (first equation below), and weak electrophilic substitution (second equation). The latter SN2 reaction is known as the Williamson Ether Synthesis, and is generally used only with 1º-alkyl halide reactants because the strong alkoxide base leads to E2 elimination of 2º and 3º-alkyl halides.

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General Ether Synthesis under Mild Acid-Free …

N2 - An enantioselective intramolecular chiral phosphoric acid-catalyzed cyclization of unsaturated acetals has been utilized for the synthesis of functionalized chiral piperidines. The chiral enol ether products of these cyclizations undergo subsequent in situ enantioenrichment through acetalization of the minor enantiomer. A new computational reaction exploration method was utilized to elucidate the mechanism and stereoselectivity of this transformation. Rather than confirming the originally postulated cyclization proceeding directly through a vinyl oxocarbenium ion, simulations identified an alternative two-step mechanism involving the formation of a mixed chiral phosphate acetal, which undergoes a concerted, asynchronous SN2′-like displacement to yield the product with stereoselectivity in agreement with experimental observations.

SYNTHESIS OF METHYL TERT-BUTYL ETHER CATALYZED …

The Bartlett synthesis (shown below) is a five step process with the ring construction occurring in the last step by an acid catalyzed reaction on an acyclic precursor.

The Acid-Catalyzed Reaction of Propionic Acid ..

Ryan R. Walvoord was born in 1986 in the small town of Williamson, NY. He received a B.S. in Chemistry from the Rochester Institute of Technology in 2007, where he performed undergraduate research in the laboratories of Professor Christina G. Collison. In the same year, he began his graduate studies at the University of Pennsylvania under the guidance of Professor Marisa C. Kozlowski. His research in the Kozlowski group has focused on the synthesis and chemistry of arylnitromethanes, as well as the spectroscopic investigation of hydrogen bonding using colorimetric sensors.

Ether synthesis by etherification (alkylation)

Sadiya Raja was born in Frankfurt, Germany in 1983. She received her Master’s degree in Chemistry from the Goethe University, Frankfurt in 2009. Thereafter she started her Ph.D. at the RWTH Aachen University under the supervision of Prof. Dr. Magnus Rueping, where she worked on the development of enantioselective Brønsted acid-catalyzed pericylic reactions and the synthesis of chiral N-heterocycles. She completed her Ph.D. in December 2012 and is currently a lab head at Bachem, Switzerland.

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