通过 - 碳中心的二极根通过压力,空气稳定的环的合成
Xinmou Wang1, Peiqi Zhang1, Zhiyi Yang1
1Department of Chemistry, The Hong Kong University of Science and Technology, Hong Kong SAR, China.
Nature chemistry
|April 24, 2025
概括
研究人员开发了一种新的催化方法来合成具有挑战性的四个成员的环. 这一进步使得能够创建多样化,稳定的玻拉循环,在材料科学和医学中具有潜在的应用.
科学领域:
- 有机化学 有机化学
- 材料科学 材料科学 材料科学
- 药用化学 医学化学
背景情况:
- 与碳类似物相比,玻璃环是有价值的支架,具有独特的特性.
- 在批准的药物中,五个成员的oxaboracycles至关重要,而六个成员的系统可以增强分子材料.
- 由于合成的挑战和固有的环应变,四个成员的环未被充分探索.
研究的目的:
- 开发高效的合成路径,用于以前无法获得的四个成员环.
- 探索含的新型异环化合物的特性和应用.
- 通过受控的循环反应扩大玻拉环结构的多样性.
主要方法:
- 使用三重能量转移催化剂用于-碳中心二极根的分子内合.
- 调节基质的π-结合和激发能来控制循环化通路 (1,6-和1,5-).
- 采用无金属,中性反应条件,用于广泛的基板范围和稳定性.
主要成果:
- 通过二基合成功合成了稳定在空气中的玻里 (四个环).
- 实现了正式的1,6和1,5环化,产生二博林和二cyclopropaborol衍生物.
- 产生结构多样化的玻拉环,足够稳定,可以通过柱状染色学净化.
结论:
- 开发了一种通用的催化方法,用于合成紧张的四个成员环.
- 证明了制造多种环的能力,包括氧环和化多环芳.
- 突出了这些新型玻拉环在光电子和药物发现方面的应用潜力.
相关概念视频
02:36Regioselectivity and Stereochemistry of Hydroboration
8.0K
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...
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...
8.0K
03:08Hydroboration-Oxidation of Alkenes
7.6K
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.
7.6K
02:47Alkynes to Aldehydes and Ketones: Hydroboration-Oxidation
17.6K
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.
17.6K
02:29Conformations of Cycloalkanes
11.4K
Adolf von Baeyer attempted to explain the instabilities of small and large cycloalkane rings using the concept of angle strain — the strain caused by the deviation of bond angles from the ideal 109.5° tetrahedral value for sp3 hybridized carbons. However, while cyclopropane and cyclobutane are strained, as expected from their highly compressed bond angles, cyclopentane is more strained than predicted, and cyclohexane is virtually strain-free. Hence, Baeyer’s theory that...
11.4K
![[4+2] Cycloaddition of Conjugated Dienes: Diels–Alder Reaction](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2Ffiles%2Fmedia%2Fscience-education%2Fscience-education-thumbs%2F12417.jpg&w=3840&q=75)
01:16[4+2] Cycloaddition of Conjugated Dienes: Diels–Alder Reaction
9.8K
The Diels–Alder reaction is an example of a thermal pericyclic reaction between a conjugated diene and an alkene or alkyne, commonly referred to as a dienophile. The reaction involves a concerted movement of six π electrons, four from the diene and two from the dienophile, forming an unsaturated six-membered ring. As a result, these reactions are classified as [4+2] cycloadditions.
9.8K
01:27Radical Substitution: Allylic Bromination
4.9K
In organic synthesis, the formation of products can be altered by changing the reaction conditions. For example, a dibromo addition product is formed when propene is treated with bromine at room temperature. In contrast, propene undergoes allylic substitution in non-polar solvents at high temperatures to give 3-bromopropene. In order to avoid the addition reaction, the bromine concentration must be kept as low as possible throughout the reaction. This can be achieved using...
4.9K