Ligand Promoted Pd-Catalyzed High para-Selective C-H Olefination
Shuo-Jie Shen1, Yao-Dong Li1, Ye Ge1
1State Key Laboratory of Materials-Oriented Chemical Engineering, School of Pharmaceutical Sciences, Nanjing Tech University, Nanjing 210009, China.
Organic Letters
|December 15, 2023
Summary
Researchers developed a new method for para-selective C-H olefination of benzoic acid derivatives. Ligand screening improved para-selectivity from 62:38 to 96:4, enabling efficient synthesis of para-substituted products.
Area of Science:
- Organic Chemistry
- Catalysis
- Synthetic Methodology
Background:
- Achieving para-selective C-H functionalization in benzoic acid derivatives is challenging due to potential ortho-activation by the carbonyl group.
- Directed C-H functionalization strategies often face competition between different reactive sites.
Purpose of the Study:
- To develop a ligand-promoted method for high para-selective C-H olefination of benzoic acid derivatives.
- To overcome the challenge of ortho-C-H activation and improve selectivity towards the para-position.
Main Methods:
- Screening of various ligands to identify optimal candidates for promoting para-selectivity.
- Utilizing a designed template strategy to direct C-H functionalization.
- Optimization of reaction conditions for C-H olefination.
Main Results:
- Identified specific ligands that significantly enhance para-selectivity in C-H olefination.
- Increased the ratio of para-substituted products to other isomers from 62:38 to 96:4.
- Demonstrated a robust method for constructing para-substituted benzoic acid derivatives.
Conclusions:
- Ligand design is crucial for achieving high para-selectivity in C-H functionalization of benzoic acid derivatives.
- The developed method offers an efficient route for synthesizing valuable para-substituted benzoic acid compounds.
- This approach has potential applications in medicinal chemistry and materials science.
Related Concept Videos
02:17Reduction of Alkenes: Asymmetric Catalytic Hydrogenation
3.3K
Catalytic hydrogenation of alkenes is a transition-metal catalyzed reduction of the double bond using molecular hydrogen to give alkanes. The mode of hydrogen addition follows syn stereochemistry.
The metal catalyst used can be either heterogeneous or homogeneous. When hydrogenation of an alkene generates a chiral center, a pair of enantiomeric products is expected to form. However, an enantiomeric excess of one of the products can be facilitated using an enantioselective reaction or an...
The metal catalyst used can be either heterogeneous or homogeneous. When hydrogenation of an alkene generates a chiral center, a pair of enantiomeric products is expected to form. However, an enantiomeric excess of one of the products can be facilitated using an enantioselective reaction or an...
3.3K
02:35Regioselectivity of Electrophilic Additions-Peroxide Effect
8.6K
In the presence of organic peroxides, the addition of hydrogen bromide to an alkene yields the isomer that is not predicted by Markovnikov’s rule. For example, the addition of hydrogen bromide to 2-methylpropene in the presence of peroxides gives 1-bromo-2-methylpropane. This addition reaction proceeds via a free radical mechanism, which reverses the regioselectivity. The free radical reaction mechanism involves three stages: initiation, propagation, and termination.
8.6K
02:36Regioselectivity and Stereochemistry of Hydroboration
8.2K
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...
8.2K
02:17Regioselectivity of Electrophilic Additions to Alkenes: Markovnikov's Rule
14.2K
If a set of reactants can yield multiple constitutional isomers, but one of the isomers is obtained as the major product, the reaction is said to be regioselective. In such reactions, bond formation or breaking is favored at one reaction site over others.
The hydrohalogenation of an unsymmetrical alkene can yield two haloalkane products, depending on which vinylic carbon takes up the halogen. However, one product usually predominates, where hydrogen adds to the vinylic carbon bearing the...
The hydrohalogenation of an unsymmetrical alkene can yield two haloalkane products, depending on which vinylic carbon takes up the halogen. However, one product usually predominates, where hydrogen adds to the vinylic carbon bearing the...
14.2K
02:24Reduction of Alkynes to cis-Alkenes: Catalytic Hydrogenation
7.7K
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.
7.7K
01:25Radical Anti-Markovnikov Addition to Alkenes: Overview
3.4K
The addition of hydrogen bromide to alkenes in the presence of hydroperoxides or peroxides proceeds via an anti-Markovnikov pathway and yields alkyl bromides.
3.4K