通过Tris (三氧) 氧变体揭示塔卡伊氧化剂
Daniel Werner1, Reiner Anwander1
1Institut für Anorganische Chemie , Eberhard Karls Universität Tübingen , Auf der Morgenstelle 18 , 72076 Tübingen , Germany.
Journal of the American Chemical Society
|September 15, 2018
概括
研究人员分离了塔凯的olefination试剂,一种基于的甲基复合物. 这种新的复合物和相关物种有效地进行化反应, 提供了对这种重要的有机转化机制的洞察力.
科学领域:
- 有机金属化学
- 合成有机化学
- 催化剂
背景情况:
- 塔凯化是一种合成乙烯化物的有价值方法.
- 塔凯化反应中的活性物种很难分离和描述.
- 了解活性试剂的精确性质对于优化反应至关重要.
研究的目的:
- 为了分离和表征涉及塔凯化过程中的难以捉摸的甲基 (III) 复合物.
- 为了研究分离的复合物的反应性.
- 通过研究分离的试剂的选择性来阐明塔凯化机制.
主要方法:
- 通过前体与 (CHI3) 的反应合成甲基复合物.
- 新型复合物的分离和表征,包括[Cr2Cl4 (CHI) (thf) ]和[CrII/III2I2 (OSi) (O tBu) 3) (CHI2) ].
- 单独复合物的选,以检测它们促进甲的单体化,并分析立体选择性 (E/Z异构).
主要成果:
- 甲基 (Cr) 复合物[Cr2Cl4 (CHI) (thf) ]和混合价值复合物[CrII/III2I2 (OSi) (O tBu) 3) (CHI2) ]的分离.
- 这两种分离的复合物都在促进甲的化过程中表现出有效性.
- [Cr2Cl4 ((CHI)) ((thf)) ]表现出与原始Takai试剂相似的E选择性,而[CrII/III2I2 ((OSi)) ((O tBu)) 2 ((CHI2)) ]表现出偏好的Z选择性.
结论:
- 该研究成功地分离了关键的-甲基复合物,从而直接获得了Takai的潜在活性物种.
- 观察到的立体选择性支持一种假设,即单甲基物种是塔凯化中的活性成分.
- 这些发现有助于更好地理解塔凯的炼机制,并为试剂设计提供了新的途径.
更多相关视频
13:31Novel Atomic Force Microscopy Based Biopanning for Isolation of Morphology Specific Reagents against TDP-43 Variants in Amyotrophic Lateral Sclerosis
Published on: February 12, 2015
9.2K
09:22Functional Assessment of BRCA1 variants using CRISPR-Mediated Base Editors
Published on: February 28, 2021
6.0K
相关概念视频
02:30Histone Variants at the Centromere
5.1K
Histone variants are the histone proteins with structural and sequence variations. These variants may be regarded as “mutant” forms that replace their canonical histone counterparts in the nucleosomes. Specific post-translational modifications on the histone variants enable further chromatin complexity and regulate tissue-specific gene expression. The most common histone variants are from histone H2A, H2B, and linker histone H1 families. However, several variants of histone H3...
5.1K
01:13Olefin Metathesis Polymerization: Overview
2.6K
Recently, the development of olefin metathesis polymerization advanced the field of polymer synthesis. Simply put, the reorganization of substituents on their double bonds between two olefins in the presence of a catalyst is known as the olefin metathesis reaction. The use of metathesis reaction for polymer synthesis is called olefin metathesis polymerization.
Ruthenium-based Grubbs catalyst is the most commonly used catalyst for olefin metathesis polymerization. Grubbs catalyst consists of a...
Ruthenium-based Grubbs catalyst is the most commonly used catalyst for olefin metathesis polymerization. Grubbs catalyst consists of a...
2.6K
01:26EDTA: Auxiliary Complexing Reagents
1.4K
EDTA titrations are usually carried out in highly basic conditions, where the fully deprotonated form of EDTA, Y4−, actively complexes with the free metal ions in the solution. Several metal ions precipitate as hydrous oxide (hydroxides, oxides, or oxyhydroxides) under these conditions, lowering the concentration of free metal ions in the solution. For this reason, auxiliary complexing agents or ligands such as ammonia, tartrate, citrate, or triethanolamine are used in EDTA titrations to...
1.4K
00:53Olefin Metathesis Polymerization: Acyclic Diene Metathesis (ADMET)
2.2K
Acyclic diene metathesis polymerization or ADMET polymerization involves cross-metathesis of terminal dienes, such as 1,8-nonadiene, to give linear unsaturated polymer and ethylene. As ADMET is a reversible process, the formed ethylene gas must be removed from the reaction mixture to complete the polymerization process.
Similar to cross-metathesis, ADMET also involves the formation of metallacyclobutane intermediate by [2+2] cycloaddition of one of the double bonds of a terminal diene with...
Similar to cross-metathesis, ADMET also involves the formation of metallacyclobutane intermediate by [2+2] cycloaddition of one of the double bonds of a terminal diene with...
2.2K
01:14Acid Halides to Ketones: Gilman Reagent
4.1K
Lithium dialkyl cuprate, also known as Gilman reagents, selectively reduces acid halides to ketones. The acid chloride is treated with Gilman reagent at −78 °C in the presence of ether solution to produce a ketone in good yield.
As shown below, the mechanism proceeds in two steps. First, one of the alkyl groups of the reagent acts as a nucleophile and attacks the acyl carbon of the acid chloride to form a tetrahedral intermediate. This is followed by the reformation of the carbon–oxygen...
As shown below, the mechanism proceeds in two steps. First, one of the alkyl groups of the reagent acts as a nucleophile and attacks the acyl carbon of the acid chloride to form a tetrahedral intermediate. This is followed by the reformation of the carbon–oxygen...
4.1K
01:16Olefin Metathesis Polymerization: Ring-Opening Metathesis Polymerization (ROMP)
3.2K
Ring-opening metathesis polymerization or ROMP involves strained cycloalkenes as starting materials. The mechanism of ROMP proceeds by reacting cycloalkene with Grubbs catalyst to give metallacyclobutane intermediate which undergoes a ring-opening reaction to form new carbene. The new carbene reacts with another molecule of cycloalkene. Repetition of these steps leads to the formation of an unsaturated open-chain polymer product. All these steps are reversible, however, relieving the ring...
3.2K