有機化学. オーガニック・ケミストリー. 実用的なオレフィンヒドロアミネーションは,ニトロアルネスによるものです
Jinghan Gui1, Chung-Mao Pan1, Ying Jin1
1Department of Chemistry, Scripps Research Institute, La Jolla, CA 92037, USA.
Science (New York, N.Y.)
|May 23, 2015
まとめ
この研究では,オレフィンとニトロヘテロアレンから二次アミンを合成するための新しい方法が紹介されています. 効率的で化学的選択性の高いプロセスは,様々な機能群を許容し,アミン合成のための多用途の代替案を提供します.
科学分野:
- 有機化学 オーガニック・ケミストリー
- 合成化学 合成化学とは
背景:
- アミンの合成と機能化は,様々な化学応用において極めて重要です.
- アリルアミンの合成のための既存の方法は,基板の範囲と機能群の許容性に制限があります.
研究 の 目的:
- 二次アミンを合成するための新しい,効率的で,化学選択的な方法を開発する.
- オレフィンやニトロ・ヘテロ・アレンなどの容易に入手可能な原料化学物質を活用する.
主な方法:
- オレフィンとニトロ・ヘテロ・アレンとの反応を伴う新しい合成プロトコル.
- アミンの形成のための,推定される根幹媒介経路の探査.
- 100以上の基板組み合わせのスクリーニングにより,反応の範囲と機能群の耐性を評価する.
主要な成果:
- 2次アミンの合成は,正式なオレフィン・ヒドロアミネーションによって成功しました.
- 高い化学選択性が達成され,ステリカルに阻害されたアミンの合成が可能になりました.
- アルコール,アミン,ボロン酸を含む多数の無保護機能群に対する耐性が実証されています.
- ブックワルド・ハートウィッグとウルマン結合のような確立された方法の正交性,アリルハリドとカルボニル化合物を許容する.
結論:
- 開発されたプロトコルは,二次アミンへのシンプルで,操作的には簡単で,多用途な経路を提供します.
- この方法は,アミンの合成のためのツールキットを拡張し,特に敏感な機能群を持つ複雑な分子のために.
関連する概念動画
01:29Preparation of Amines: Reduction of Oximes and Nitro Compounds
4.9K
Oximes can be reduced to primary amines using catalytic hydrogenation, hydride reduction, or sodium metal reduction. The reduction of aliphatic and aromatic nitro compounds to primary amines takes place by either catalytic hydrogenation or by using active metals like Fe, Zn, and Sn in the presence of an acid.
Though catalytic hydrogenation can reduce nitrobenzenes, the reduction is nonselective in the presence of other functional groups. For instance, if nitrobenzene contains an aldehyde group,...
Though catalytic hydrogenation can reduce nitrobenzenes, the reduction is nonselective in the presence of other functional groups. For instance, if nitrobenzene contains an aldehyde group,...
4.9K
02:47Alkynes to Aldehydes and Ketones: Hydroboration-Oxidation
22.0K
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.
22.0K
03:08Hydroboration-Oxidation of Alkenes
12.5K
In addition to the oxymercuration–demercuration method, which converts the alkenes to alcohols with Markovnikov orientation, a complementary hydroboration-oxidation method yields the anti-Markovnikov product. The hydroboration reaction, discovered in 1959 by H.C. Brown, involves the addition of a B–H bond of borane to an alkene giving an organoborane intermediate. The oxidation of this intermediate with basic hydrogen peroxide forms an alcohol.
12.5K
01:19Preparation of Carboxylic Acids: Hydrolysis of Nitriles
6.7K
Nitriles (R–CN) can be converted into carboxylic acids (R–COOH) upon treatment with aqueous acids, i.e., upon hydrolysis of nitriles. Under base-catalyzed conditions, carboxylate anions (R–COO−) are formed.
6.7K
02:36Regioselectivity and Stereochemistry of Hydroboration
9.8K
A significant aspect of hydroboration–oxidation is the regio- and stereochemical outcome of the reaction.
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.
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.
9.8K
01:12Preparation of Nitriles
2.8K
One of the common methods to prepare nitriles is the dehydration of amides. This method requires strong dehydrating agents like phosphorous pentoxide or boiling acetic anhydride for converting amides to nitriles. Another reagent namely, thionyl chloride also accomplishes the dehydration of amides, where amide acts as a nucleophile. The first step of the mechanism involves the nucleophilic attack by the amide on the thionyl chloride to form an intermediate. In the next step, the electron pairs...
2.8K