Palladium-Catalyzed Cascade Cyclization/Alkynylation Reactions.
Jianxiao Li1, Shaorong Yang1, Wanqing Wu1
1Key Laboratory of Functional Molecular Engineering of Guangdong Province, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou, 510640, China.
Chemistry, an Asian Journal
|October 23, 2019
Summary
Palladium-catalyzed cascade reactions, particularly cyclization/alkynylation, efficiently construct complex molecular skeletons. This review details various palladium-catalyzed cascade cyclization strategies and their applications.
Area of Science:
- Organic Chemistry
- Catalysis
- Synthetic Methodology
Background:
- Palladium-catalyzed cascade reactions are crucial for efficient synthesis.
- Cascade cyclization/alkynylation reactions offer access to diverse molecular architectures.
Purpose of the Study:
- To summarize and discuss recent advancements in palladium-catalyzed cascade cyclization/alkynylation reactions.
- To highlight key synthetic methodologies, applications, and mechanisms.
Main Methods:
- Review of literature on palladium-catalyzed cascade cyclization/alkynylation.
- Focus on oxypalladation, aminopalladation, intramolecular Heck-type reactions, and carbocyclizations.
Main Results:
- Detailed discussion of various palladium-catalyzed cascade cyclization strategies.
- Examples of constructing monocyclic, bicyclic, polycyclic, and spirocyclic compounds are presented.
- Mechanistic insights into different cascade pathways are provided.
Conclusions:
- Palladium-catalyzed cascade cyclization/alkynylation reactions are powerful tools for synthesizing complex organic molecules.
- These methods demonstrate excellent chemoselectivity and broad applicability in organic synthesis.
More Related Videos
![Mizoroki-Heck Cross-coupling Reactions Catalyzed by Dichloro{bis[1,1',1''-phosphinetriyltripiperidine]}palladium Under Mild Reaction Conditions](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F51444.jpg&w=3840&q=50)
Related Concept Videos
02:24Reduction of Alkynes to cis-Alkenes: Catalytic Hydrogenation
8.9K
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.
8.9K
02:27Preparation of Alkynes: Alkylation Reaction
11.9K
Introduction
Alkylation of terminal alkynes with primary alkyl halides in the presence of a strong base like sodium amide is one of the common methods for the synthesis of longer carbon-chain alkynes. For example, treatment of 1-propyne with sodium amide followed by reaction with ethyl bromide yields 2-pentyne.
Alkylation of terminal alkynes with primary alkyl halides in the presence of a strong base like sodium amide is one of the common methods for the synthesis of longer carbon-chain alkynes. For example, treatment of 1-propyne with sodium amide followed by reaction with ethyl bromide yields 2-pentyne.
11.9K
02:47Alkynes to Aldehydes and Ketones: Hydroboration-Oxidation
20.5K
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.
20.5K
01:16Cycloaddition Reactions: Overview
3.3K
Cycloadditions are one of the most valuable and effective synthesis routes to form cyclic compounds. These are concerted pericyclic reactions between two unsaturated compounds resulting in a cyclic product with two new σ bonds formed at the expense of π bonds. The [4 + 2] cycloaddition, known as the Diels–Alder reaction, is the most common. The other example is a [2 + 2] cycloaddition.
3.3K
02:17Reduction of Alkenes: Asymmetric Catalytic Hydrogenation
3.8K
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...
3.8K
01:17Ziegler–Natta Chain-Growth Polymerization: Overview
3.8K
Ziegler–Natta polymerization is another form of addition or chain‐growth polymerization used for synthesizing linear polymers over branched polymers. The catalyst used for polymerization is the Ziegler–Natta catalyst, named after Karl Ziegler and Giulio Natta, who developed it in 1953. This catalyst is an organometallic complex of titanium tetrachloride and triethyl aluminum, with the active form of the catalyst being an alkyl titanium compound. Using the Ziegler–Natta...
3.8K