リチウムカルバマートにおけるNからCのアリル移行:ベンジルアルコールのアルファアリレーション
関連する実験動画
Updated: Jun 25, 2026

10:44
Isolating Free Carbenes, their Mixed Dimers and Organic Radicals
Published on: April 19, 2019
Jonathan Clayden1, William Farnaby, Damian M Grainger
1School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, UK. clayden@man.ac.uk
Journal of the American Chemical Society
|March 12, 2009
まとめ
研究者らは,リチア化O-ベンジルカルバメトで新しいN-to-Cアリレーションを発見した. この反応により,α,α-arylated アルコールが生成され,これまでに知られている方法よりもエネルギー要求が低い新しい合成経路が提供されます.
科学分野:
- 有機化学 オーガニック・ケミストリー
- 合成方法論 合成方法論
- コンピューティング・ケミストリー
背景:
- 炭酸塩酸は,有機合成における多用途の機能群である.
- 炭酸塩のN-アルキル化は確立されていますが,N-アリレーションはユニークな課題です.
- C-C結合形成のための新しい方法の開発は,複雑な分子を合成するために不可欠です.
研究 の 目的:
- リチア化O-ベンジルカルバマートのN-アリル置換剤による新しいN-to-Cアリレーションを報告する.
- アルファ,アルファ-アリレート二次および三次アルコールへの新しい合成経路を確立する.
- このアリレーション反応のメカニズムを計算的方法を使って解明する.
主な方法:
- N-アリルO-ベンジルカルバメトを強い塩基 (リチウム化) で処理する.
- アリレートされた製品の分離と特性.
- 反応経路とエネルギー学を研究するための密度関数理論 (DFT) 計算.
主要な成果:
- 新しい反応様式が観察されました:リチア化時にクリーンなN-to-Cアリル転送.
- この反応は,アルファ,アルファ-二酸化アルコールへの直接的な経路を提供します.
- DFTの計算は,アシル移転と比較してエネルギー的に有利な dearomatizing 攻撃メカニズムを示しています.
結論:
- リチア化N-アリルO-ベンジルカルバマートは,ユニークなN-to-Cアリレーションをします.
- この変換は,高度に置換されたアルコールを合成するための貴重な方法を提供します.
- 提案された dearomatizing 攻撃メカニズムは,観察された反応性とその効率性を説明します.
関連する概念動画
Nucleophilic Aromatic Substitution: Elimination–Addition
Simple aryl halides do not react with nucleophiles. However, nucleophilic aromatic substitutions can be forced under certain conditions, such as high temperatures or strong bases. The mechanism of substitution under such conditions involves the highly unstable and reactive benzyne intermediate. Benzyne contains equivalent carbon centers at both ends of the triple bond, each of which is equally susceptible to nucleophilic attack. This 50–50 distribution of products is confirmed through isotopic...
α-Alkylation of Ketones via Enolate Ions
Ketones with α protons are deprotonated by strong bases like lithium diisopropylamide (LDA) to form enolate ions. The anion is stabilized by resonance, and its hybrid structure exhibits negative charges on the carbonyl oxygen and the α carbon. This ambident nucleophile can attack an electrophile via two possible sites: the carbonyl oxygen, known as O-attack, or the α carbon, known as C-attack. The nucleophilic attack via the carbanionic site is preferred. This is due to the strong interaction...
Preparation of Alkynes: Alkylation Reaction
Introduction
Alkylation of terminal alkynes with primary alkyl halides in the presence of a strong base like sodium amide is one of the common methods for the synthesis of longer carbon-chain alkynes. For example, treatment of 1-propyne with sodium amide followed by reaction with ethyl bromide yields 2-pentyne.
Alkylation of terminal alkynes with primary alkyl halides in the presence of a strong base like sodium amide is one of the common methods for the synthesis of longer carbon-chain alkynes. For example, treatment of 1-propyne with sodium amide followed by reaction with ethyl bromide yields 2-pentyne.
Nucleophilic Aromatic Substitution of Aryldiazonium Salts: Aromatic SN1
Treating arylamines with nitrous acid gives aryldiazonium salts that are effective substrates in nucleophilic aromatic substitution reactions. The diazonio group in these salts can be easily displaced by different nucleophiles, yielding a wide variety of substituted benzenes. The leaving group departs as nitrogen gas, and this easy elimination is the driving force for the substitution reaction.
In the Sandmeyer reaction, for example, the diazonio group is replaced by a chloro, bromo, or cyano...
In the Sandmeyer reaction, for example, the diazonio group is replaced by a chloro, bromo, or cyano...
Electrophilic Aromatic Substitution: Friedel–Crafts Acylation of Benzene
The Friedel–Crafts acylation reactions involve the addition of an acyl group to an aromatic ring. These reactions proceed via electrophilic aromatic substitution by employing an acyl chloride and a Lewis acid catalyst such as aluminum chloride to form aryl ketone.
Carbocations
Carbocations are one of the reaction intermediates formed during several nucleophilic substitutions or elimination reactions. A carbocation is an electron-deficient species with the central carbon atom having six electrons and three bonded atoms. The central carbon in a carbocation is sp2 hybridized with trigonal planar geometry. It has an empty p orbital perpendicular to the plane of the structure that can accept electrons. Thus, carbocations act as strong electrophiles and may react with any...

