終端アルキンの鉄触媒ビニルジケーション
Qiang Huang1, Yu-Xuan Su1, Wei Sun1
1Frontiers Science Center for New Organic Matter, the State Key Laboratory and Institute of Elemento-Organic Chemistry, College of Chemistry, Nankai University, Tianjin 300071, China.
この研究では,終末アルキンのビニルシンク化のための新しい鉄触媒法が導入されています. このアプローチは,以前の方法の限界を克服し,多様な有機亜鉛反応剤を効率的に合成します.
科学分野:
- 有機金属化学
- 合成有機化学
背景:
- オルガノジン反応剤は合成に不可欠です.
- アルキンカルボジネーションは,アルキンの末端耐性および難しい製品変換によって制限されます.
研究 の 目的:
- 末端アルキンのビニルシンク化のための新しい方法を開発する.
- 多種多様な有機亜鉛反応剤を合成し,効率と機能群の耐性を向上させる.
主な方法:
- 1,10-フェナントロリン-イミンのリガンドを持つ新たに開発された鉄触媒を使用した.
- ビニル亜鉛反応剤と末端アルキンを基板として使用した.
主要な成果:
- ターミナルアルキンの効率的なビニルシンク化を達成した.
- 機能的グループに対する優れた耐性 (アミノ,エステル,ヒドロキシルなど) そして広範囲の基板 (アリル,アルケニル,アルキルアセチレン)
- 高い化学選択性,地域選択性,ステレオ選択性を示した.
結論:
- 新しい鉄触媒法により,新しい有機亜鉛反応剤が利用できる.
- 特定のリガンドを持つ鉄触媒は,活性と選択性において他の金属に優れている.
- この方法はビタミンAのような 生物活性分子の合成を促進します
さらに関連する動画
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09:54Chemoselective Preparation of 1-Iodoalkynes, 1,2-Diiodoalkenes, and 1,1,2-Triiodoalkenes Based on the Oxidative Iodination of Terminal Alkynes
Published on: September 12, 2018
関連する概念動画
02:27Preparation of Alkynes: Alkylation Reaction
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.
02:24Reduction of Alkynes to cis-Alkenes: Catalytic Hydrogenation
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.
02:35Electrophilic Addition to Alkynes: Hydrohalogenation
02:47Alkynes to Aldehydes and Ketones: Hydroboration-Oxidation
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.
02:38Electrophilic Addition to Alkynes: Halogenation
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.
02:42Acidity of 1-Alkynes
The acidic strength of hydrocarbons follows the order: Alkynes > Alkenes > Alkanes. The strength of an acid is commonly expressed in units of pKa — the lower the pKa, the stronger the acid. Among the hydrocarbons, terminal alkynes have lower pKa values and are, therefore, more acidic. For example, the pKa values for ethane, ethene, and acetylene are 51, 44, and 25, respectively, as shown here.