アリルディアゾニウム塩を用いたモノアリレートアセタルデヒドの連続流合成
Natalia Chernyak1, Stephen L Buchwald
1Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States.
Journal of the American Chemical Society
|July 21, 2012
まとめ
この研究では,アセタルデヒドエノラートのアルファアリレーションを達成するために,アニリンとエチルビニルエーテルを使用して新しい合成方法を導入しています. このプロセスは,価値ある化合物を生成するために,高機能群互換性を提供します.
科学分野:
- 有機化学 オーガニック・ケミストリー
- 合成化学 合成化学とは
背景:
- カルボニル化合物のアルファアリレーションは,有機合成における重要な変換である.
- この反応のための効率的で汎用的な方法の開発は,依然として活発な研究分野です.
研究 の 目的:
- アセタルデヒドエノラートのアルファアリレーションのための新しい合成経路を提示する.
- この変換における前駆体としてのアニリンとエチルビニルエーテルの有用性を実証する.
主な方法:
- アニリンとエチルビニルエーテルを原料として利用する.
- 直接のエノラートアリレーションの合成対価として機能するプロセスを開発.
主要な成果:
- この反応は効率的に進行し,アセタルデヒドエノラートアルファ-アリレーションの合成 ekvivalent として作用する.
- この方法は,優れた機能群互換性を示しています.
- この方法によって,合成的に価値のある化合物がいくつか作られました.
結論:
- 記述されたプロセスは,有機化学者のための貴重な新しいツールを提供します.
- 高い機能群耐性は,多様で複雑な分子の合成を可能にします.
関連する概念動画
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01:21Acid-Catalyzed α-Halogenation of Aldehydes and Ketones
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02:27Preparation 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.
01:07Alkylation of β-Ketoester Enolates: Acetoacetic Ester Synthesis
Acetoacetic ester synthesis is a method to obtain ketones from alkyl halides and β-keto esters. The reaction occurs in the presence of an alkoxide base that abstracts the acidic proton of the β-keto esters. The step results in an enolate ion which is doubly stabilized. The enolate then reacts with an alkyl halide via the SN2 process to produce an alkylated ester intermediate with a new C–C bond. The hydrolysis of the intermediate, followed by acidification, results in an alkylated β-keto acid.
02:34Preparation of Alkynes: Dehydrohalogenation
Introduction
Alkynes can be prepared by dehydrohalogenation of vicinal or geminal dihalides in the presence of a strong base like sodium amide in liquid ammonia. The reaction proceeds with the loss of two equivalents of hydrogen halide (HX) via two successive E2 elimination reactions.
Alkynes can be prepared by dehydrohalogenation of vicinal or geminal dihalides in the presence of a strong base like sodium amide in liquid ammonia. The reaction proceeds with the loss of two equivalents of hydrogen halide (HX) via two successive E2 elimination reactions.
02:42Acidity of 1-Alkynes
The acidic strength of hydrocarbons follows the order: Alkynes > Alkenes > Alkanes. The strength of an acid is commonly expressed in units of pKa — the lower the pKa, the stronger the acid. Among the hydrocarbons, terminal alkynes have lower pKa values and are, therefore, more acidic. For example, the pKa values for ethane, ethene, and acetylene are 51, 44, and 25, respectively, as shown here.