三核チタンポリ水化物複合体による一酸化炭素の水素酸化サイクロテトラメリゼーション
Shaowei Hu1, Takanori Shima1,2, Zhaomin Hou1,2
1Organometallic Chemistry Laboratory, RIKEN Cluster for Pioneering Research, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
Journal of the American Chemical Society
|November 10, 2020
まとめ
チタンポリヒドリド複合体は,一酸化炭素 (CO) の水解酸素化サイクロテトラメリゼーションを達成した. この反応により,ガンマブチロラクトンやサイクロブタノンのような 有用な化学物質に変換される中間産物が生じる.
科学分野:
- 有機金属化学
- キャタリシス
- 無機化学
背景:
- 化学において,一酸化炭素 (CO) の還元結合は極めて重要です.
- 金属水素は,CO変換の主要な触媒である.
- CO利用のための新しい触媒経路の開発は不可欠です.
研究 の 目的:
- COの新型水解酸素化サイクロテトラメリゼーションを報告する.
- 三核のチタンポリ水素複合体とCOの反応性を調査する.
- COから付加価値の化学物質の合成を研究する.
主な方法:
- 炭素一酸化物 (CO) と三核のチタンポリ水化物複合体[C5Me4SiMe3) Ti]3[μ3-H][μ2-H]6が−78 °Cで反応する.
- エタン-1,2-ジルとサイクロブテン-3,4-ジル-1,2-二酸化物を含む反応中間物の特徴
- 最終製品を得るための中間物の水解と酸解.
主要な成果:
- CO二酸化によるエーテン-1,2-ジル種の形成.
- サイクロブテン-3,4-ジル-1,2-二酸化物単位を形成する.
- 中間物質をテトラヒドロサイクロブテン-1,2-二酸化塩酸,サイクロブテン-2-イル-1酸化塩酸,ガンマブチロラクトン,サイクロブタンに変換する.
結論:
- 三核のチタンポリ水化物複合体は,前例のないCOの水酸化性サイクロテトラメリゼーションを容易にする.
- この研究は,COを複雑な有機構造に変換するための新しい経路を示しています.
- 方法論はガンマブチロラクトンやサイクロブタノンのような貴重な化学原料へのアクセスを提供します.
関連する概念動画
01:22Alkenes via Reductive Coupling of Aldehydes or Ketones: McMurry Reaction
2.2K
The radical dimerization of ketones or aldehydes gives vicinal diols through a pinacol coupling reaction. However, the behavior of titanium metals used for the reaction as a source of electrons is unusual. When the reaction is carried out in the presence of titanium, diols can be isolated at low temperatures. Else titanium further reacts with diols, forming alkenes through the McMurry reaction.
2.2K
01:26Thermal and Photochemical Electrocyclic Reactions: Overview
2.7K
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.
2.7K
02:44Oxidation of Alkenes: Syn Dihydroxylation with Osmium Tetraoxide
12.0K
Alkenes are converted to 1,2-diols or glycols through a process called dihydroxylation. It involves the addition of two hydroxyl groups across the double bond with two different stereochemical approaches, namely anti and syn. Dihydroxylation using osmium tetroxide progresses with syn stereochemistry.
12.0K
01:17Thermal Electrocyclic Reactions: Stereochemistry
2.3K
The stereochemistry of electrocyclic reactions is strongly influenced by the orbital symmetry of the polyene HOMO. Under thermal conditions, the reaction proceeds via the ground-state HOMO.
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
2.3K
03:08Hydroboration-Oxidation of Alkenes
10.4K
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.
10.4K
01:18Aromatic Hydrocarbon Cations: Structural Overview
3.5K
Cycloheptatriene is a neutral monocyclic unsaturated hydrocarbon that consists of an odd number of carbon atoms and an intervening sp3 carbon in the ring. The three double bonds in the ring correspond to 6 π electrons, which is a Huckel number, and therefore satisfies the criteria of 4n + 2 π electrons. However, the intervening sp3 carbon disrupts the continuous overlap of p orbitals. As a result, cycloheptatriene is not aromatic.
Removing one hydrogen from the intervening CH2 group...
Removing one hydrogen from the intervening CH2 group...
3.5K