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Updated: Jun 20, 2025

Retropinacol/Cross-pinacol Coupling Reactions - A Catalytic Access to 1,2-Unsymmetrical Diols

Retropinacol/Cross-pinacol Coupling Reactions - A Catalytic Access to 1,2-Unsymmetrical Diols

Published on: April 4, 2014

Pd-催化 C(sp²) -H/C(sp²) -H 烯的合

Marco Di Matteo¹, Anna Gagliardi¹, Alexandre Pradal¹

¹Institut Parisien de Chimie Moléculaire (IPCM), Faculté des Sciences et Ingénierie, CNRS, Sorbonne Université, 4 Place Jussieu, 75005 Paris, France.

The Journal of organic chemistry

|July 18, 2024

概括

这项研究表明了利蒙的新型化合反应,产生了新的1,3-二烯化合物. 这种方法为合成复杂有机分子提供了一条途径.

科学领域:

有机化学有机化学
催化剂是一种催化剂.
合成方法论合成方法论

背景情况:

直接C-H功能化是现代有机合成的一个关键策略.
利蒙是一种易于获得的烯,是选择性C-H激活的具有挑战性的基质.
开发高效的C-H/C-H合的催化系统仍然是一个活跃的研究领域.

研究的目的:

开发使用烯的区域选择性二催化Csp2H/Csp2H合反应.
探索这种与各种不和的合作伙伴结合的范围.
用密度函数理论 (DFT) 计算来阐明反应机制.

主要方法:

(II) 催化直接C (sp2) -H/C (sp2) -H的烯与缺电子的基和基的合.
密度函数理论 (DFT) 计算用于机械研究.
通过Sonogashira合在细胞催化下对联产品的后功能化.

主要成果:

烯与烯酸/胺,α,β不和,烯和酸的成功区域选择性合.
形成新的1,3-二烯结构.
实验和DFT结果一致,支持拟议的催化循环.
通过微粒索诺加希拉合来证明大规模的后功能化.

结论:

已经建立了一个新的和高效的PdII催化Csp2H/Csp2H合方法,用于利蒙.
反应提供了对有价值的1,3-二烯支架的访问.
该研究提供了机械的见解,并证明了产品在进一步的合成转化中的实用性.

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Vicinal Diols via Reductive Coupling of Aldehydes or Ketones: Pinacol Coupling Overview

Vicinal Diols via Reductive Coupling of Aldehydes or Ketones: Pinacol Coupling Overview

Wilhelm Rudolph Fittig discovered the pinacol coupling reaction in 1859. It is a radical dimerization reaction and involves the reductive coupling of aldehydes or ketones in the presence of hydrocarbon solvent to yield vicinal diols.

[4+2] Cycloaddition of Conjugated Dienes: Diels–Alder Reaction

[4+2] Cycloaddition of Conjugated Dienes: Diels–Alder Reaction

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.

Preparation of Diols and Pinacol Rearrangement

Preparation of Diols and Pinacol Rearrangement

Compounds bearing two hydroxyl groups are known as diols. When the hydroxyl groups are located on adjacent carbon atoms, the diols are called vicinal diols or glycols. Under acidic conditions, vicinal diols undergo a specific reaction called pinacol rearrangement.
The reaction begins with transferring a proton from the acid catalyst to one of the hydroxyl groups, producing an oxonium ion.

Photochemical Electrocyclic Reactions: Stereochemistry

Photochemical Electrocyclic Reactions: Stereochemistry

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

Thermal Electrocyclic Reactions: Stereochemistry

Thermal Electrocyclic Reactions: Stereochemistry

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.

Alkenes via Reductive Coupling of Aldehydes or Ketones: McMurry Reaction

Alkenes via Reductive Coupling of Aldehydes or Ketones: McMurry Reaction

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.