イリジウム触媒 sp3 炭化水素溶媒におけるC-Hボリレーション 2,2'-ジピリデリルメタンリガンドによって可能
Margaret R Jones1, Caleb D Fast1, Nathan D Schley1
1Department of Chemistry, Vanderbilt University, Nashville, Tennessee 27235, United States.
Journal of the American Chemical Society
|March 24, 2020
まとめ
ディピリデリルメタンリガンドを含む新しいイリジウム触媒は,アルカンC-Hボリレーションの効率を改善する. この方法は原子経済と基板の互換性を高め,炭化水素溶媒での反応を可能にします.
科学分野:
- 有機金属化学
- カタリシス
- 有機合成
背景:
- イリジウム触媒によるアルケンのC-Hボリレーションは,限られたボロン反応剤の利用ときれいな基板の必要性のために,伝統的に貧弱な原子経済に苦しんでいます.
- 既存の方法は,しばしば高い基板過剰を必要とし,機能群の許容性が限られており,より広範な合成アプリケーションを妨げています.
研究 の 目的:
- イリジウム触媒による高効率のアルケンのC-Hボリレーションシステムを開発し,原子の経済性を向上させ,基板の範囲を広げる.
- 触媒性能を向上させる新しいディピリデリルメタンリガンドの有効性を調査する.
主な方法:
- 特別に設計されたディピリデリルメタンリガンドを含むイリジウム複合体の合成と適用.
- 炭化水素溶媒を用いた従来の乾燥条件と改変条件の両方で,触媒活性の評価.
- 機能群の互換性と基板の適用範囲の評価,挑戦的な極性機能を含む.
主要な成果:
- 新型リガンドは,高度に活性なアルカンボリレーション触媒を促進し,ディボロン反応剤の完全な消費を達成し,製品の2モール相当を生産しました.
- システムは,低触媒負荷で効果的に動作し,炭化水素溶媒内の活性化されていないアルカンのボリレーションを可能にし,基板の過剰を減少させます.
- 機能群の互換性が向上し,以前には反応しない極性機能を持つ基板の成功ボリル化も示された.
結論:
- 開発されたディピリデリルメタンリガンドベースのイリジウム触媒は,アルカンC-Hボリレーションの効率と範囲を大幅に高めます.
- このブレークスルーは,有機合成における有用性を拡大し,C-H機能化に対するより原子経済的で汎用的なアプローチを提供します.
さらに関連する動画
関連する概念動画
Alkynes to Aldehydes and Ketones: Hydroboration-Oxidation
20.4K
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.
20.4K
Regioselectivity and Stereochemistry of Hydroboration
9.2K
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.
9.2K
Hydroboration-Oxidation of Alkenes
10.8K
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.
10.8K
Electrophilic 1,2- and 1,4-Addition of X2 to 1,3-Butadiene
3.3K
Electrophilic addition of halogens to alkenes proceeds via a cyclic halonium ion to form a 1,2-dihalide or a vicinal dihalide.
3.3K
Electrophilic 1,2- and 1,4-Addition of HX to 1,3-Butadiene
7.3K
The electrophilic addition of hydrogen halides such as HBr to alkenes and nonconjugated dienes gives a single product as per Markovnikov’s rule.
7.3K
Radical Substitution: Hydrogenolysis of Alkyl Halides with Tributyltin Hydride
2.2K
Radical substitution reactions can be used to remove functional groups from molecules. The hydrogenolysis of alkyl halides is one such reaction, where the weak Sn–H bond in tributyltin hydride reacts with alkyl halides to form alkanes. Here, the reagent Bu3SnH yields tributyltin halide as a byproduct.
The bonds formed in this reaction are stronger than the bonds broken, making it energetically favorable. The reaction follows a radical chain mechanism similar to radical halogenation reactions,...
The bonds formed in this reaction are stronger than the bonds broken, making it energetically favorable. The reaction follows a radical chain mechanism similar to radical halogenation reactions,...
2.2K

![[DPEPhosbcpCu]PF6: A General and Broadly Applicable Copper-Based Photoredox Catalyst](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F59739.jpg&w=3840&q=50)
