RETRACTED:アリファティックアミドとエステルの非対称遠隔C-Hボリレーション
Ronald L Reyes1,2, Miyu Sato2, Tomohiro Iwai2
1Institute for Chemical Reaction Design and Discovery (WPI-ICReDD), Hokkaido University, Sapporo 001-0021, Japan.
Science (New York, N.Y.)
|August 22, 2020
まとめ
この研究は,アミドとエステルのC−H結合を精密に修正するための新しい触媒法を導入している. このプロセスは高い選択性を達成し,合成のための価値あるキラル構成要素の作成を可能にします.
科学分野:
- 有機化学
- カタリシス
- 合成化学
背景:
- C−H結合の機能化は有機合成において極めて重要です.
- アリファティック・スキャフォールドで 場所の選択性とステレオ制御を 達成することは依然として困難です
- 遠隔機能化,特にカルボニル基への γ は困難である.
研究 の 目的:
- 高度にエナチオセレクティブでサイトセレクティブの触媒性ボリレーション法を開発する.
- アミドとエステルにおける遠隔C ((sp3) -H結合 (ガンマからカルボニル) を機能化する.
- 生成されたキラル・ボリレイテッド化合物の合成有用性を実証する.
主な方法:
- イリジウム基のCH活性化触媒の組み立て
- 触媒成分には,キラルモノフォスフィートリガンドと尿素ピリジン受容体が含まれる.
- ボリル化のためにピナコラトボリル基を使用した.
- 触媒と基板の相互作用を理解するために 量子化学計算を用いた.
主要な成果:
- 遠隔C ((sp3) -H結合の高度なエナンチオセレクティブとサイトセレクティブの触媒性ボリレーションを達成した.
- γ位置で二次および三次アミドおよびエステルを機能化しました.
- 触媒は酵素のような空洞を形成し,非共性相互作用によって基板結合を促進します.
- エナチオ濃縮の γ-ボリルカルボキシル酸の多用途性を実証した.
結論:
- C-H機能化に挑戦する新しい触媒システムを開発した.
- この方法は貴重なキラル中間物質へのアクセスを提供します.
- 酵素のような空洞を備えた触媒の設計は,その選択性の鍵です.
![Solid-phase Synthesis of [4.4] Spirocyclic Oximes](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F58508.jpg&w=3840&q=50)
関連する概念動画
02:17Reduction of Alkenes: Asymmetric Catalytic Hydrogenation
3.7K
Catalytic hydrogenation of alkenes is a transition-metal catalyzed reduction of the double bond using molecular hydrogen to give alkanes. The mode of hydrogen addition follows syn stereochemistry.
The metal catalyst used can be either heterogeneous or homogeneous. When hydrogenation of an alkene generates a chiral center, a pair of enantiomeric products is expected to form. However, an enantiomeric excess of one of the products can be facilitated using an enantioselective reaction or an...
The metal catalyst used can be either heterogeneous or homogeneous. When hydrogenation of an alkene generates a chiral center, a pair of enantiomeric products is expected to form. However, an enantiomeric excess of one of the products can be facilitated using an enantioselective reaction or an...
3.7K
02:36Regioselectivity 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
02:47Alkynes to Aldehydes and Ketones: Hydroboration-Oxidation
20.3K
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.
20.3K
01:25Radical Anti-Markovnikov Addition to Alkenes: Overview
3.9K
The addition of hydrogen bromide to alkenes in the presence of hydroperoxides or peroxides proceeds via an anti-Markovnikov pathway and yields alkyl bromides.
3.9K
02:24Reduction of Alkynes to cis-Alkenes: Catalytic Hydrogenation
8.8K
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.
8.8K
02:27Preparation of Alkynes: Alkylation Reaction
11.7K
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.
11.7K