メチル-N-ヘテロアロマティックをアルコールで触媒アルキル化
1Anorganische Chemie II, Universität Bayreuth, 95440 Bayreuth, Germany.
Journal of the American Chemical Society
|January 6, 2010
まとめ
新しいイリジウム触媒反応は,アルコールを用いてN-ヘテロアロマティックメチル基を効率的にアルキル化します. この新しいC-C結合法では,おそらく水素を借りているが,様々な異環化合物の汎用的な合成を提供している.
科学分野:
- 有機化学 オーガニック・ケミストリー
- カタリシス カタリシス カタリシス
- 合成方法論 合成方法論
背景:
- N-ヘテロアロマティック化合物は,医薬品と材料において極めて重要です.
- N-ヘテロアロマティックにメチル基を効率的にアルキル化することは,合成的に難しい.
- 既存の方法は,しばしば厳しい条件や特殊な反応剤を必要とします.
研究 の 目的:
- N-ヘテロアロマティックメチル基をアルキル化するための新しい触媒C-C結合反応を導入する.
- 主要アルコールをアルキル化剤として利用した効率的な合成プロトコルを開発する.
- 新しい反応の範囲とメカニズムを探求する.
主な方法:
- イリジウム触媒反応システムの開発.
- 主要アルコールをアルキル基の持続可能な供給源として利用する.
- 借用水素 (または水素自動伝送) 機構の調査.
- ピリミジン,ピラジン,ピリダジン,ピコリンを含む様々なN-ヘテロアロマト基板の試験.
主要な成果:
- N-ヘテロアロマティックで置換されたメチル群の効率的なアルキル化が達成されました.
- 反応は軽度な条件下で進行し,すぐに入手可能な一次アルコールを使用します.
- 幅広い基板の範囲が実証され,多様なヘテロサイクルの構造に対応しました.
- 触媒システムは高い効率と選択性を示した.
結論:
- N-ヘテロアロマティックアルキル化のための新しい効率的な触媒C-C結合反応が確立されました.
- この方法は,機能化されたヘテロサイクルにアクセスするための貴重な合成ツールを提供します.
- 水素を借りるメカニズムは,この変換のためのエレガントな経路を提供します.
さらに関連する動画
関連する概念動画
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.
02:47Alkynes to Aldehydes and Ketones: Hydroboration-Oxidation
Introduction
One of the convenient methods for the preparation of aldehydes and ketones is via hydration of alkynes. Hydroboration-oxidation of alkynes is an indirect hydration reaction in which an alkyne is treated with borane followed by oxidation with alkaline peroxide to form an enol that rapidly converts into an aldehyde or a ketone. Terminal alkynes form aldehydes, whereas internal alkynes give ketones as the final product.
One of the convenient methods for the preparation of aldehydes and ketones is via hydration of alkynes. Hydroboration-oxidation of alkynes is an indirect hydration reaction in which an alkyne is treated with borane followed by oxidation with alkaline peroxide to form an enol that rapidly converts into an aldehyde or a ketone. Terminal alkynes form aldehydes, whereas internal alkynes give ketones as the final product.
02:24Reduction of Alkynes to cis-Alkenes: Catalytic Hydrogenation
Introduction
Like alkenes, alkynes can be reduced to alkanes in the presence of transition metal catalysts such as Pt, Pd, or Ni. The reaction involves two sequential syn additions of hydrogen via a cis-alkene intermediate.
Like alkenes, alkynes can be reduced to alkanes in the presence of transition metal catalysts such as Pt, Pd, or Ni. The reaction involves two sequential syn additions of hydrogen via a cis-alkene intermediate.
02:15Preparation of Alcohols via Addition Reactions
Overview
The acid-catalyzed addition of water to the double bond of alkenes is a large-scale industrial method used to synthesize low-molecular-weight alcohols. An acidic atmosphere is required to allow the hydrogen in the water molecule to act as an electrophile and attack the double bond in an alkene. The addition of a proton to the double bond creates a carbocation intermediate. The proton preferentially bonds to the less substituted end of the double bond to create a more stable carbocation...
The acid-catalyzed addition of water to the double bond of alkenes is a large-scale industrial method used to synthesize low-molecular-weight alcohols. An acidic atmosphere is required to allow the hydrogen in the water molecule to act as an electrophile and attack the double bond in an alkene. The addition of a proton to the double bond creates a carbocation intermediate. The proton preferentially bonds to the less substituted end of the double bond to create a more stable carbocation...
03:08Hydroboration-Oxidation of Alkenes
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.
01:19Aldehydes and Ketones with Alcohols: Hemiacetal Formation
Similar to water, alcohols can add to the carbonyl carbon of the aldehydes and ketones. The addition of one molecule of alcohol to the carbonyl compound forms the hemiacetal or half acetal. As depicted below, in a hemiacetal, the carbon is directly linked to an OH and OR group.