メタラフォトレドックス触媒における光化学的限界の克服:赤光駆動C-Nクロスカップリング
Samantha L Goldschmid1, Nicholas Eng Soon Tay1, Candice L Joe2
1Department of Chemistry, Columbia University, New York, New York10027, United States.
Journal of the American Chemical Society
|November 23, 2022
まとめ
深赤または近赤外線は,メタラフォトレドックス触媒によってアリルアミネーションを強化します. この低エネルギー光は反応のスケーラビリティを改善し,望ましくない水分分解副産物を抑制します.
科学分野:
- 有機化学
- キャタリシス
- 写真化学
背景:
- アリルアミネーションは医薬品,材料,微細化学物質の合成に不可欠です.
- 青い光を用いたメタラフォトレドックス触媒はC-Nクロスカップリングに有効ですが,光の浸透が弱く,水解塩化などの副作用があるため,スケーラビリティの問題に直面しています.
- 低エネルギー (深赤/近赤外線) の光は,よりよく浸透し,潜在的に副作用を軽減することができます.
研究 の 目的:
- アリルアミネーションのための金属フォトレドックス触媒の低エネルギー光 (深赤/近赤外線) の使用を調査する.
- 低エネルギー光が望ましい反応性を強化し,水分分解を抑制することを実証する.
- 副産物の形成を減少させるメカニズムを探求する.
主な方法:
- 深赤または近赤外線照射を用いる.
- 触媒システムにオスミウム光触媒を使用した.
- (ヘテロ) アリルブロミドとアミンヌクレオフィルの範囲を調査した.
主要な成果:
- 低エネルギー光を用いたアリルアミネーションが成功し,基板の範囲を拡大した.
- 高エネルギー光の方法と比較して,水解塩素化副産物の形成を大幅に最小限に抑えました.
- 高エネルギー光は,アリル-ニッケル結合の直接光分解を誘導し,アリルラジカルを生成し,副反応を促進すると仮定した.
結論:
- 低エネルギー光 (深赤/近赤外線) は,メタルフォトレドックス触媒によるアリルアミネーションの実行可能で有利な代替手段である.
- このアプローチは,ブルーライトの限界を克服し,水分分解を抑制することにより,スケーラビリティと選択性を改善します.
- この発見は,より効率的で工業的に重要なC-Nクロスカップリング反応の道を開く.
関連する概念動画
Photochemical Electrocyclic Reactions: Stereochemistry
1.9K
The absorption of UV–visible light by conjugated systems causes the promotion of an electron from the ground state to the excited state. Consequently, photochemical electrocyclic reactions proceed via the excited-state HOMO rather than the ground-state HOMO. Since the ground- and excited-state HOMOs have different symmetries, the stereochemical outcome of electrocyclic reactions depends on the mode of activation; i.e., thermal or photochemical.
Selection Rules: Photochemical Activation
Selection Rules: Photochemical Activation
1.9K
Cycloaddition Reactions: MO Requirements for Photochemical Activation
2.2K
Some cycloaddition reactions are activated by heat, while others are initiated by light. For example, a [2 + 2] cycloaddition between two ethylene molecules occurs only in the presence of light. It is photochemically allowed but thermally forbidden.
2.2K
The Photochemical Reaction Center
4.2K
Reaction centers are pigment-protein complexes that initiate energy conversion from photons to chemical entities. Therefore, photochemical reaction center is a more appropriate term that describes these complexes. The Nobel laureates Robert Emerson and William Arnold provided the first experimental evidence of photochemical reaction centers by demonstrating the participation of nearly 2,500 chlorophyll molecules for the release of just one molecule of oxygen. Despite thousands of photosynthetic...
4.2K
Thermal and Photochemical Electrocyclic Reactions: Overview
2.4K
Electrocyclic reactions are reversible reactions. They involve an intramolecular cyclization or ring-opening of a conjugated polyene. Shown below are two examples of electrocyclic reactions. In the first reaction, the formation of the cyclic product is favored. In contrast, in the second reaction, ring-opening is favored due to the high ring strain associated with cyclobutene formation.
2.4K
The Z-Scheme of Electron Transport in Photosynthesis
10.4K
The light reactions of photosynthesis assume a linear flow of electrons from water to NADP+. During this process, light energy drives the splitting of water molecules to produce oxygen. However, oxidation of water molecules is a thermodynamically unfavorable reaction and requires a strong oxidizing agent. This is accomplished by the first product of light reactions: oxidized P680 (or P680+), the most powerful oxidizing agent known in biology. The oxidized P680 that acquires an electron from the...
10.4K
Reduction of Alkynes to cis-Alkenes: Catalytic Hydrogenation
7.9K
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.
7.9K
![[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)
![Cercosporin-Photocatalyzed [4+1]- and [4+2]-Annulations of Azoalkenes Under Mild Conditions](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F60786.jpg&w=3840&q=50)
