アルケンの制御可能,順序的,およびステレオ選択的C-Hアリルアルキル化
Ling Qin1, Mohammed Sharique1, Uttam K Tambar1
1Department of Biochemistry , The University of Texas Southwestern Medical Center , 5323 Harry Hines Boulevard , Dallas , Texas 75390-9038 , United States.
Journal of the American Chemical Society
|October 16, 2019
まとめ
研究者は,アルケンのC−H結合を炭素基に順次置き換えるための新しい銅触媒方法を開発した. このアプローチにより,選択性が高い単純な起始材料から複雑な分子を合成することができます.
科学分野:
- 有機化学
- カタリシス
- 合成方法論
背景:
- 直接的なC−H結合機能化は,効率的な合成に不可欠である.
- メチル群を四次中心に順次変換することは困難です.
- アリルC-H機能化は 複雑な構造への経路を提供します
研究 の 目的:
- アリル位置での連続的なC−H結合置換のための一般的で制御可能な方法を開発する.
- 単純なアルケーンとグリナード反応剤から 多様で複雑な分子を作製する.
- アリルアルキル化において高い選択性とエナンチオコントロールを達成する.
主な方法:
- 末端アルケンの銅触媒による連続アルキル化.
- 高い分岐選択性のために電子に富んだビアリルフォスフィンリガンドを使用した.
- エナチオセレクティブ合成のためのキラル・フォスフィン・リガンドを使用.
主要な成果:
- プロピレンと他のアルケンのアリル位置で3つのC-H結合をうまく置き換えた.
- アリルアルキル化製品において高い分岐選択性を達成した.
- キラル・コッパー・カタリシスによるエナチオ濃縮製品の生成が実証された.
結論:
- 開発された方法は,単純な原料から複雑な分子を構築するための強力なツールを提供します.
- このアプローチは選択的で制御可能な 炭素中心への経路を提供する.
- C-H活性化により,多様で有価な化学物質の合成を可能にします.
関連する概念動画
02:24Reduction of Alkynes to cis-Alkenes: Catalytic Hydrogenation
8.9K
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.
8.9K
02:17Regioselectivity of Electrophilic Additions to Alkenes: Markovnikov's Rule
16.0K
If a set of reactants can yield multiple constitutional isomers, but one of the isomers is obtained as the major product, the reaction is said to be regioselective. In such reactions, bond formation or breaking is favored at one reaction site over others.
The hydrohalogenation of an unsymmetrical alkene can yield two haloalkane products, depending on which vinylic carbon takes up the halogen. However, one product usually predominates, where hydrogen adds to the vinylic carbon bearing the...
The hydrohalogenation of an unsymmetrical alkene can yield two haloalkane products, depending on which vinylic carbon takes up the halogen. However, one product usually predominates, where hydrogen adds to the vinylic carbon bearing the...
16.0K
01:10α-Alkylation of Ketones via Enolate Ions
3.7K
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...
3.7K
02:17Reduction of Alkenes: Asymmetric Catalytic Hydrogenation
3.8K
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...
3.8K
02:34Regioselectivity and Stereochemistry of Acid-Catalyzed Hydration
9.4K
The rate of acid-catalyzed hydration of alkenes depends on the alkene's structure, as the presence of alkyl substituents at the double bond can significantly influence the rate.
9.4K
01:25Radical Anti-Markovnikov Addition to Alkenes: Overview
3.9K
The addition of hydrogen bromide to alkenes in the presence of hydroperoxides or peroxides proceeds via an anti-Markovnikov pathway and yields alkyl bromides.
3.9K