ロジウム (III) 触媒によるアルキネスの分子間水酸化反応
Derek J Schipper1, Marieke Hutchinson, Keith Fagnou
1Centre for Catalysis Research and Innovation, Department of Chemistry, University of Ottawa, 10 Marie Curie, Ottawa, Ontario, Canada K1N 6N5. dschi064@uottawa.ca
Journal of the American Chemical Society
|May 6, 2010
まとめ
ロジウム ((III) 触媒は,高地域選択性を持つ内部アルキンの効率的な水酸化を可能にします. この方法は,様々なアルキンとアレンで機能し,分子間反応に挑戦するためにアレンメタリングを経由して進行します.
科学分野:
- 有機化学 オーガニック・ケミストリー
- 有機金属化学 有機金属化学
- カタリシス カタリシス カタリシス
背景:
- ハイドロアリレーション反応は,炭素-炭素結合の形成に不可欠である.
- 内部アルキンの機能化のための触媒システムを開発することは,依然として課題です.
- ロジウム触媒は有機合成においてユニークな反応経路を提供します.
研究 の 目的:
- 内部アルキンの水利化のためのロジウム (III) 触媒法を開発する.
- 反応の地域選択性と基質の範囲を調査する.
- 反応メカニズムを解明するために.
主な方法:
- カチオンロジウム ((III)) 触媒を用いて.
- 内部アルキンが様々なアレンと反応する.
- アレンメタレーションを含むメカニズムに関する予備的な研究を行う.
主要な成果:
- 内部アルキンの多様な範囲で良い収穫量を達成しました.
- 非対称的に置換されたアルキンと優れた地域選択性を示した.
- さまざまなアレン基板を使用して,良い収穫が得られました.
- 主なメカニズム的なステップとしてアレンメタレーションを特定しました.
結論:
- 開発されたロジウム ((III) -触媒化水酸化は,内部アルキンの機能化のための効果的な方法である.
- この反応は,広範囲の基板範囲と高い地域選択性を示しています.
- このメカニズムはアレンメタレーションを伴うため,複雑な分子間結合を容易にする.
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.
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.
02:35Electrophilic Addition to Alkynes: Hydrohalogenation
Electrophilic addition of hydrogen halides, HX (X = Cl, Br or I) to alkenes forms alkyl halides as per Markovnikov's rule, where the hydrogen gets added to the less substituted carbon of the double bond. Hydrohalogenation of alkynes takes place in a similar manner, with the first addition of HX forming a vinyl halide and the second giving a geminal dihalide.
02:38Electrophilic Addition to Alkynes: Halogenation
Introduction
Halogenation is another class of electrophilic addition reactions where a halogen molecule gets added across a π bond. In alkynes, the presence of two π bonds allows for the addition of two equivalents of halogens (bromine or chlorine). The addition of the first halogen molecule forms a trans-dihaloalkene as the major product and the cis isomer as the minor product. Subsequent addition of the second equivalent yields the tetrahalide.
Halogenation is another class of electrophilic addition reactions where a halogen molecule gets added across a π bond. In alkynes, the presence of two π bonds allows for the addition of two equivalents of halogens (bromine or chlorine). The addition of the first halogen molecule forms a trans-dihaloalkene as the major product and the cis isomer as the minor product. Subsequent addition of the second equivalent yields the tetrahalide.
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.
02:34Preparation of Alkynes: Dehydrohalogenation
Introduction
Alkynes can be prepared by dehydrohalogenation of vicinal or geminal dihalides in the presence of a strong base like sodium amide in liquid ammonia. The reaction proceeds with the loss of two equivalents of hydrogen halide (HX) via two successive E2 elimination reactions.
Alkynes can be prepared by dehydrohalogenation of vicinal or geminal dihalides in the presence of a strong base like sodium amide in liquid ammonia. The reaction proceeds with the loss of two equivalents of hydrogen halide (HX) via two successive E2 elimination reactions.