オープンチェーンペプチドベースの触媒による非対称なアジデーション-サイクロアジデーション. トリアゾールへの連続的なエナンチオセレクティブ経路
David J Guerin1, Scott J Miller
1Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467-3860, USA.
Journal of the American Chemical Society
|March 7, 2002
まとめ
研究者らは,ベータ置換ヒスティジンペプチドを合成して,触媒のエナチオ選択性を改善した. このアプローチにより,非対称なアジダ化反応が強化され,光学的に濃縮されたトリアゾールとトリアゾリンが得られました.
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
- アシンメトリック・シンセシス
背景:
- ヒスティジンを含むペプチドは,汎用的な触媒です.
- ノンコヴァレントコンフォーメーション硬化とは,触媒の性能を向上させる戦略である.
- エナチオセレクティビティは,キラル分子の合成に不可欠です.
研究 の 目的:
- ベータ置換ヒスティジンを含むペプチドを合成するために.
- 触媒のエナチオセレクティブ性に対する非共性型構成硬化の効果を調査する.
- 開発された触媒を非対称合成で適用する.
主な方法:
- ベータ置換ヒスティジンを含むペプチドの一族の合成.
- アジドをアルファ,ベータ不飽和カルボキシラート誘導体への結合添加において,触媒のエナチオ選択性の評価.
- 連続した非対称なアジデーション/サイクロアディション反応における応用.
主要な成果:
- エナチオセレクティビティの明瞭な強化が実証されています.
- 連続した非対称なアジデーション/サイクロアジデーションで成功アプリケーションを達成しました.
- 光学的に濃縮されたトリアゾールとトリアゾリンを合成した.
結論:
- ベータ置換ヒスティジンを含むペプチドは,非共性型コンフォメーション硬化を通じたエナチオ選択性を効果的に強化します.
- 開発された触媒システムは,光学的に濃縮されたトリアゾールとトリアゾリンの合成に適用できます.
- この研究は,効率的なキラル触媒の設計のための新しい戦略を提供します.
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.
02:15Preparation 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...
02:26Base-Catalyzed Ring-Opening of Epoxides
Due to their highly strained structures, epoxides can readily undergo ring-opening reactions through nucleophilic substitution, either in the presence of an acid or a base. The nucleophilic substitution reactions in the presence of acid are called acid-catalyzed ring-opening reactions, and nucleophilic substitution reactions in the presence of a base are called base-catalyzed ring-opening reactions. Epoxides undergo base-catalyzed ring-opening reactions in the presence of a strong nucleophile...
01:08Base-Catalyzed Aldol Addition Reaction
As depicted in Figure 1, base-catalyzed aldol addition involves adding two carbonyl compounds in aqueous sodium hydroxide to form a β-hydroxy carbonyl compound.
01:15Acid-Catalyzed Aldol Addition Reaction
The aldol reaction of a ketone under acidic conditions successfully forms an unsaturated carbonyl as the final product instead of an aldol. The acid-catalyzed aldol reaction is depicted in Figure 1.