JoVE - Journal of Visualized Experiments
JoVE Visualize
Contact Us
このページは機械翻訳されています。他のページは英語で表示される場合があります。 View in English

化学酵素触媒による二酸化炭素をl-エリスルロースに還元性オリゴメリゼーション

  • 0LCC-CNRS, Université de Toulouse, CNRS, F-31077 Toulouse Cedex 4, France.
Journal of the American Chemical Society +

|

2021年9月21日

PubMedで要約を見る

まとめ

この要約は機械生成です。

関連する概念動画

Oxidation of Alkenes: Syn Dihydroxylation with Osmium Tetraoxide 02:44

11.1K

Alkenes are converted to 1,2-diols or glycols through a process called dihydroxylation. It involves the addition of two hydroxyl groups across the double bond with two different stereochemical approaches, namely anti and syn. Dihydroxylation using osmium tetroxide progresses with syn stereochemistry.

Syn Dihydroxylation Mechanism
The reaction comprises a two-step mechanism. It begins with the addition of osmium tetroxide across the alkene double bond in a concerted manner forming a...

[3,3] Sigmatropic Rearrangement of Allyl Vinyl Ethers: Claisen Rearrangement 01:24

2.3K

The Claisen rearrangement is a [3,3] sigmatropic rearrangement of allyl vinyl ethers to unsaturated carbonyl compounds. The rearrangement is a concerted pericyclic reaction proceeding via a chair-like transition state.

An aromatic Claisen rearrangement involves the conversion of allyl aryl ethers to an unstable ketone intermediate, which tautomerizes to give ortho-substituted phenols.

However, ortho-substituted allyl aryl ethers exclusively yield para-substituted phenols via two sequential...

Hydroboration-Oxidation of Alkenes 03:08

9.4K

In addition to the oxymercuration–demercuration method, which converts the alkenes to alcohols with Markovnikov orientation, a complementary hydroboration-oxidation method yields the anti-Markovnikov product. The hydroboration reaction, discovered in 1959 by H.C. Brown, involves the addition of a B–H bond of borane to an alkene giving an organoborane intermediate. The oxidation of this intermediate with basic hydrogen peroxide forms an alcohol.

Borane as a reagent is very reactive, as the...

Regioselective Formation of Enolates 01:33

2.9K

As depicted in the figure below, the unsymmetrical ketones can form two possible enolates:  less substituted or more substituted enolates. Usually, the thermodynamic enolates are formed from the more substituted α-carbon atom, while the kinetic enolates are formed faster by deprotonation from the less substituted position. The thermodynamic enolates have lower energy, so they are  more stable. But the energy required to form kinetic enolates is less.

This regioselectivity in...

Reduction of Alkenes: Asymmetric Catalytic Hydrogenation 02:17

3.5K

Catalytic hydrogenation of alkenes is a transition-metal catalyzed reduction of the double bond using molecular hydrogen to give alkanes. The mode of hydrogen addition follows syn stereochemistry.
The metal catalyst used can be either heterogeneous or homogeneous. When hydrogenation of an alkene generates a chiral center, a pair of enantiomeric products is expected to form. However, an enantiomeric excess of one of the products can be facilitated using an enantioselective reaction or an...

Dehydration of Aldols to Enones: Acid-Catalyzed Aldol Condensation 00:43

2.5K

As shown in Figure 1, under acidic conditions, the β-hydroxy ketone undergoes dehydration via an E1 elimination reaction to form an enone.

Figure 1. The dehydration reaction of a β-hydroxy ketone.
Figure 2 depicts the sequential processes involved in the mechanism of the reaction. Here, the acid protonates the hydroxyl group in the β-hydroxy ketone to form a hydrated hydroxyl group, which then departs to form a tertiary carbocation intermediate. Subsequently, the loss of the hydrogen atom...