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Updated: Mar 5, 2026
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Isolating Free Carbenes, their Mixed Dimers and Organic Radicals
Published on: April 19, 2019
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ボランによって誘発されたアルケン-カルベン同体化:非対称ディボレンへのアクセス
Wei Lu1, Yongxin Li1, Rakesh Ganguly1
1Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, and ‡NTU-CBC Crystallography Facility, Nanyang Technological University , 637371, Singapore.
Journal of the American Chemical Society
|March 24, 2017
まとめ
研究者は,サイクル (アルキル) (アミノ) カーベン (cAAC) とボランを用いて新しいディボレン化合物を合成した. この研究は,ディボレンの極化性質と,そのB,Nを含むメチレンサイクロプロパン誘導体への変換を明らかにする.
科学分野:
- オーガノボロン化学
- 炭酸塩化学
- メイングループ元素の化学
背景:
- サイクル (アルキル) (アミノ) カーベン (cAACs) は,有機金属化学における多用途リガンドである.
- ボランは合成と触媒でよく使用される反応性種です.
- ボロン-ボロン二重結合を特徴とする化合物であるディボレンは,そのユニークな電子特性のために重要な関心を持っています.
研究 の 目的:
- cAACを使用したディボレン化合物の新合成経路を開発する.
- 電子構造と非対称ディボレンの反応性を調べる
- ディボレンを他のボロン含有構造に変換することを研究する.
主な方法:
- 1,2-水素移動によるcAAC-ボラン添加物の合成.
- 非対称ディボレン (cAAC·(Br) BB ((Br) IDip 6) の分離と完全な特徴づけ
- ディボレンの電子特性を分析するためのスペクトロスコピク (11B NMR),X線 difraktion,および計算研究.
- ディボレンとイソニトリルの反応により,新しいB,Nを含む化合物が形成される.
主要な成果:
- 新型非対称ディボレン,cAAC·(Br) BB ((Br) ·IDip 6が成功して合成され,特徴づけられた.
- 電子構造の分析により,ディボレン内の偏振B2分子が明らかになった.
- ディボレンのBB二重結合は,イソニトリルとの反応によって完全に裂けることができる.
- 新しい塩基安定化B,Nを含むメチレンサイクロプロパン派生体 (7) が形成された.
結論:
- 開発された合成方法論は,新しいディボレン構造にアクセスできます.
- 非対称なディボレンはユニークな電子極化を示し,さらなる反応性研究のための機会を提供します.
- BB結合の分裂とメチレンサイクロプロパン誘導体の形成は,ディボレンの汎用的な反応性を示している.
関連する概念動画
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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.
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Hydroboration proceeds in a concerted fashion with the attack of borane on the π bond, giving a cyclic four-centered transition state. The –BH2 group is bonded to the less substituted carbon and –H to the more substituted carbon. The concerted nature requires the simultaneous addition of –H and –BH2 across the same face of the alkene giving syn stereochemistry.
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Halogenation is the addition of chlorine or bromine across the double bond in an alkene to yield a vicinal dihalide. The reaction occurs in the presence of inert and non-nucleophilic solvents, such as methylene chloride, chloroform, or carbon tetrachloride.
Consider the bromination of cyclopentene. Molecular bromine is polarized in the proximity of the π electrons of cyclopentene. An electrophilic bromine atom adds across the double bond, forming a cyclic bromonium ion intermediate.
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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...
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