アルケンのアルコールによる選択的触媒C-Hアルキル化
Dong-Hwan Lee1, Ki-Hyeok Kwon, Chae S Yi
1Department of Chemistry, Marquette University, Milwaukee, WI 53201-1881, USA.
Science (New York, N.Y.)
|September 17, 2011
まとめ
この研究は,アルケンとアルコールの新しい触媒性アルキル化反応を導入し,重要な炭素-炭素結合を形成します. このプロセスはルテニウム複合体を利用し,化学合成のための選択的で効率的な方法を提供します.
科学分野:
- 有機化学 オーガニック・ケミストリー
- カタリシス カタリシス カタリシス
- 持続可能な化学
背景:
- アルケンとアルコールは,重要な産業用原料である.
- 効率的なC−C結合形成は,有機合成における重要な課題である.
研究 の 目的:
- アルケンのアルコールによる選択的触媒アルキル化を開発する.
- ビニルC-Hと炭素-ヒドロキシセンターの間で炭素-炭素結合を形成する.
主な方法:
- カチオンのルテニウム複合体を利用した: [C6H6PCy3CORuH]+BF4−).
- 75°110°Cで28時間,溶液中の反応を行った.
- 予備的な研究を通じて反応機構を調査した.
主要な成果:
- アルケンのアルコールによる選択的触媒アルキル化が達成された.
- 水の損失でC-C結合の形成が実証されています.
- アミンやカルボニルを含む様々な機能群に対する耐性が観察されています.
- Friedel-Crafts型のメカニズムを排除し,ビニールC-Hの活性化を示唆した.
結論:
- アルケン・アルコールのアルキル化のための新しい選択的触媒法を開発した.
- この反応は,ビニルC-H活性化経路経由で行われます.
- この方法は,機能化された有機分子を合成するための貴重なツールを提供します.
関連する概念動画
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.
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.
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...
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...
02:15Preparation 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...
02:17Regioselectivity of Electrophilic Additions to Alkenes: Markovnikov's Rule
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...