関連する実験動画
Updated: Jun 30, 2026
16:24
Controlling the Size, Shape and Stability of Supramolecular Polymers in Water
Published on: August 2, 2012
アニオニック・スニックス・フライズの再配置:溶媒効果と混合集積物の役割
Jason C Riggs1, Kanwal J Singh, Ma Yun
1Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853-1301, USA.
Journal of the American Chemical Society
|September 19, 2008
まとめ
本研究では,様々な溶媒に含まれるリチウム二酸化プロピラミド (LDA) を使用したリチウムアリルカルバメートの生成について詳細に述べています. 研究により,これらの化合物はモノマー,ジマー,トリマーとして存在し,その後のスニッカス・フライズ再配列に影響を及ぼしていることが明らかになった.
科学分野:
- 有機金属化学 有機金属化学
- オーガニック・シンセシス オーガニック・シンセシス
- スペクトロスコーピーは,スペクトロスコーピーを用います.
背景:
- リチウムアリルカルバメートは,有機合成における重要な中間物質である.
- 結合状態を理解することは,反応機構にとって極めて重要です.
研究 の 目的:
- リチア化アリルカルバメートの形成と集積を調査する.
- スニックス・フライズの再配置のメカニズム的経路を解明する.
主な方法:
- リチウム二イソプロピラミド (LDA) を使って,様々な溶媒でリチウムアリルカルバメトを生成する.
- 核磁共振 (NMR) スペクトロスコーピーを用いた特徴付け ((6) Li, (13) C, (15) N).
- スニークス・フライズの再配置の運動学的研究.
主要な成果:
- リチウムアリルカルバメットは,溶媒の選択に応じて,モノマー,ArLi-LDA混合ジマー,ArLi-LDA混合トリマーとして存在します.
- Snieckus-Friesの再編成により,ArOLi-LDA混合ディマーとトリマーが得られます.
- 率の研究は,モノマー,ジマー,トリマーを含むメカニズムをサポートしています.
結論:
- 溶媒は,リチア化アリルカルバメートの集積状態を決定する.
- 集積状態は,スニックス・フライズの再配置メカニズムに影響を与えます.
- NMRスペクトロスコピーは,これらのオーガノリチウム種を特徴づけるのに不可欠です.
関連する概念動画
02:25SN1 Reaction: Mechanism
Kinetic studies of ionization of a tertiary halide in a protic solvent suggest that only the substrate participates in the rate-determining step (slow step). The nucleophile is involved only after the slowest step. The SN1 reaction takes place in a multiple-step mechanism.
Firstly, the haloalkane ionizes to generate a carbocation intermediate and a halide ion. This heterolytic cleavage is highly endothermic with large activation energy. The ionization of the substrate, facilitated by a polar...
Firstly, the haloalkane ionizes to generate a carbocation intermediate and a halide ion. This heterolytic cleavage is highly endothermic with large activation energy. The ionization of the substrate, facilitated by a polar...
02:15SN1 Reaction: Stereochemistry
This lesson provides an in-depth discussion of the stereochemical outcomes in an SN1 reaction.
In the first step of an SN1 reaction, the bond between the electrophilic carbon and the leaving group ionizes to generate the carbocation intermediate. The second step of the mechanism is the nucleophilic attack.
In the formed carbocation, the positively charged carbon is sp2 hybridized with a trigonal planar geometry. As all the three substituents lie on the same plane, a plane of symmetry for the...
In the first step of an SN1 reaction, the bond between the electrophilic carbon and the leaving group ionizes to generate the carbocation intermediate. The second step of the mechanism is the nucleophilic attack.
In the formed carbocation, the positively charged carbon is sp2 hybridized with a trigonal planar geometry. As all the three substituents lie on the same plane, a plane of symmetry for the...
02:23SN2 Reaction: Stereochemistry
In an SN2 reaction, the nucleophilic attack on the substrate and departure of the leaving group occurs simultaneously through a transition state. As the nucleophile approaches the substrate from the back-side, the configuration of the substrate carbon changes from tetrahedral to trigonal bipyramidal and then back to tetrahedral, leading to an inversion in the configuration of the product.
If the substrate is an achiral molecule at the α-carbon, the inversion of configuration is not observed.
If the substrate is an achiral molecule at the α-carbon, the inversion of configuration is not observed.
02:27Predicting Products: SN1 vs. SN2
Nucleophilic substitution reactions of alkyl halides can proceed via an SN1 or an SN2 mechanism. While in SN2 reactions, the nucleophile attacks the substrate simultaneously as the leaving group departs, in SN1 reactions, the substrate first dissociates to give the carbocation intermediate. Various factors such as the structure of the substrate, the strength of the nucleophile, and the nature of the solvent promote one mechanism over the other.
With increased substitution on the alkyl halide,...
With increased substitution on the alkyl halide,...
01:16Thermal Sigmatropic Reactions: Overview
Sigmatropic rearrangements are a class of pericyclic reactions in which a σ bond migrates from one part of a π system to another. These are intramolecular rearrangements where the total number of σ and π bonds remain unchanged.
Sigmatropic shifts are classified based on an order term [i, j ], where i and j indicate the number of atoms across which each end of the σ bond migrates. Below are examples of a [3,3] sigmatropic shift in 1,5-hexadiene, referred to as...
Sigmatropic shifts are classified based on an order term [i, j ], where i and j indicate the number of atoms across which each end of the σ bond migrates. Below are examples of a [3,3] sigmatropic shift in 1,5-hexadiene, referred to as...
02:26SN2 Reaction: Transition State
An SN2 reaction of an alkyl halide is a single-step process in which bond formation between the nucleophile and the substrate and bond breaking between the substrate and the halide occurs simultaneously through a transition state without forming an intermediate.
When the nucleophile approaches the electrophilic carbon with its lone pairs, the halide acts as a leaving group and moves away with the electron-pair bonded to the carbon. Dotted partial bonds represent the bonds being formed or broken...
When the nucleophile approaches the electrophilic carbon with its lone pairs, the halide acts as a leaving group and moves away with the electron-pair bonded to the carbon. Dotted partial bonds represent the bonds being formed or broken...