ケチミネスの触媒的非対称性ヒドロフォスフォニレーション
Liang Yin1, Youmei Bao, Naoya Kumagai
1Institute of Microbial Chemistry (BIKAKEN), Tokyo, 3-14-23 Kamiosaki, Shinagawa-ku, Tokyo 141-0021, Japan.
Journal of the American Chemical Society
|July 4, 2013
まとめ
この研究は,価値あるキラルアミノ酸前駆体を作るための効率的な触媒的非対称性ヒドロフォスフォニレーション反応を導入しています. 開発された方法は,回収可能な触媒を使用して,エナティオメリックに濃縮された化合物の持続可能な合成を可能にします.
科学分野:
- 有機化学 オーガニック・ケミストリー
- アシンメトリック・カタリシス
- オーガノフォスファルス 化学 化学
背景:
- チラルのα,α-非置換のα-アミノ酸は,医薬品化学における重要な構成要素である.
- これらの合成のための効率的な触媒方法の開発は,依然として重要な課題です.
研究 の 目的:
- N-チオフォスフィノイルケチミンの触媒的非対称なヒドロフォスフォニレーションを開発する.
- エナティオメリックに濃縮されたα,α-非置換α-アミノ酸のフォスフォニック酸類にアクセスを提供するために.
主な方法:
- ダイアルキルフォスフィートを用いた触媒的非対称性ヒドロフォスフォニレーションを用いる.
- N-チオホスフィノイルケチミンを基質として利用する.
- 環境温度での触媒の負荷と反応条件の最適化.
主要な成果:
- 効率的な触媒非対称性ヒドロフォスフォニレーションを0.5mol%の触媒負荷で達成しました.
- 証明された触媒の回収性と再利用性.
- ティオフォスフィノイル基を簡単に除去すると,フォスフォニック酸の類似品が得られる.
結論:
- 開発された方法は,キラルなα,α-非置換α-アミノ酸のフォスフォニック酸アナログへの持続可能で効率的な経路を提供します.
- 再利用可能な触媒は,合成の実用性と経済的実現性を高めます.
- この研究は,価値あるキラル有機リン化合物にアクセスするための合成ツールボックスを拡張します.
さらに関連する動画
関連する概念動画
02:17Reduction of Alkenes: Asymmetric Catalytic Hydrogenation
Catalytic hydrogenation of alkenes is a transition-metal catalyzed reduction of the double bond using molecular hydrogen to give alkanes. The mode of hydrogen addition follows syn stereochemistry.
The metal catalyst used can be either heterogeneous or homogeneous. When hydrogenation of an alkene generates a chiral center, a pair of enantiomeric products is expected to form. However, an enantiomeric excess of one of the products can be facilitated using an enantioselective reaction or an...
The metal catalyst used can be either heterogeneous or homogeneous. When hydrogenation of an alkene generates a chiral center, a pair of enantiomeric products is expected to form. However, an enantiomeric excess of one of the products can be facilitated using an enantioselective reaction or an...
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.
01:21Acid-Catalyzed α-Halogenation of Aldehydes and Ketones
By replacing an α-hydrogen with a halogen, acid-catalyzed α-halogenation of aldehydes or ketones yields a monohalogenated product
In the first step of the mechanism, the acid protonates the carbonyl oxygen resulting in a resonance-stabilized cation, which subsequently loses an α-hydrogen to form an enol tautomer. The C=C bond in an enol is highly nucleophilic because of the electron-donating nature of the –OH group. Consequently, the double bond attacks an electrophilic halogen to form a...
In the first step of the mechanism, the acid protonates the carbonyl oxygen resulting in a resonance-stabilized cation, which subsequently loses an α-hydrogen to form an enol tautomer. The C=C bond in an enol is highly nucleophilic because of the electron-donating nature of the –OH group. Consequently, the double bond attacks an electrophilic halogen to form a...
01:10α-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...
02:40Alkynes to Aldehydes and Ketones: Acid-Catalyzed Hydration
Introduction
Analogous to alkenes, alkynes also undergo acid-catalyzed hydration. While the addition of water to an alkene gives an alcohol, hydration of alkynes produces different products such as aldehydes and ketones.
Analogous to alkenes, alkynes also undergo acid-catalyzed hydration. While the addition of water to an alkene gives an alcohol, hydration of alkynes produces different products such as aldehydes and ketones.
01:23Aldehydes and Ketones with Amines: Imine Formation Mechanism
Imine formation involves the addition of carbonyl compounds to a primary amine. It begins with the generation of carbinolamine through a series of steps involving an initial nucleophilic attack and then several proton transfer reactions. The second part includes the elimination of water, as a leaving group, to give the imine.
Imines are formed under mildly acidic conditions. A pH of 4.5 is ideal for the reaction.
If the pH is low or the solution is too acidic, the reaction slows down in the...
Imines are formed under mildly acidic conditions. A pH of 4.5 is ideal for the reaction.
If the pH is low or the solution is too acidic, the reaction slows down in the...