Bis(catecholato)germane: an effective catalyst for Friedel-Crafts alkylation reaction
Debayan Basu1, Hari Pada Nayek1
1Department of Chemistry, Indian Institute of Technology (Indian school of Mines), Dhanbad-826004, Jharkhand, India. hpnayek@iitism.ac.in.
Dalton Transactions (Cambridge, England : 2003)
|July 5, 2022
Summary
Bis(catecholato)germane, a germanium complex, effectively catalyzes Friedel-Crafts alkylation reactions. This Lewis acid catalyst efficiently produces bis(indolyl)alkanes and nitroalkylated indoles with high yields.
Area of Science:
- Organometallic Chemistry
- Catalysis
- Organic Synthesis
Background:
- Germanium complexes are explored for catalytic applications.
- Friedel-Crafts alkylation is a fundamental organic reaction.
- Indole derivatives are important pharmaceutical building blocks.
Purpose of the Study:
- To synthesize and characterize bis(catecholato)germane complex.
- To evaluate its efficacy as a Lewis acid catalyst in Friedel-Crafts alkylation.
- To propose reaction mechanisms.
Main Methods:
- Synthesis of bis(catecholato)germane via reaction of catechol and germanium oxide.
- Characterization using FT-IR, NMR spectroscopy, and elemental analysis.
- Catalytic testing in Friedel-Crafts alkylation of indole with aldehydes and β-nitrostyrene derivatives.
Main Results:
- Bis(catecholato)germane was successfully synthesized and characterized.
- The complex demonstrated high catalytic activity in Friedel-Crafts alkylation.
- Yields of bis(indolyl)alkanes and nitroalkylated indoles reached up to 95% and 96%, respectively.
Conclusions:
- Bis(catecholato)germane is an efficient Lewis acid catalyst for Friedel-Crafts alkylation.
- The catalyst facilitates the synthesis of valuable indole derivatives.
- Proposed mechanisms provide insight into the catalytic process.
Related Concept Videos
01:17Electrophilic Aromatic Substitution: Friedel–Crafts Alkylation of Benzene
6.8K
Friedel–Crafts reactions were developed in 1877 by the French chemist Charles Friedel and the American chemist James Crafts. Friedel–Crafts alkylation refers to the replacement of an aromatic proton with an alkyl group via electrophilic aromatic substitution. A Lewis acid catalyst such as aluminum chloride reacts with an alkyl halide to form a carbocation. The resulting carbocation then reacts with the aromatic ring and undergoes a series of electron rearrangements before giving the...
6.8K
01:26Limitations of Friedel–Crafts Reactions
5.6K
Several restrictions limit the use of Friedel–Crafts reactions. First, the halogen in the alkyl halide must be attached to an sp3-hybridized carbon for the Friedel–Crafts reactions to occur. Vinyl or aryl halides do not react since the carbocations formed are unstable under the reaction conditions. Second, Friedel–Crafts alkylation is susceptible to carbocation rearrangement, and the major products obtained have a rearranged carbon skeleton. In contrast, the acylium ion is...
5.6K
01:11Electrophilic Aromatic Substitution: Friedel–Crafts Acylation of Benzene
7.4K
The Friedel–Crafts acylation reactions involve the addition of an acyl group to an aromatic ring. These reactions proceed via electrophilic aromatic substitution by employing an acyl chloride and a Lewis acid catalyst such as aluminum chloride to form aryl ketone.
7.4K
01:22Reactions of Aldehydes and Ketones: Baeyer–Villiger Oxidation
4.3K
Baeyer–Villiger oxidation converts aldehydes to carboxylic acids and ketones to esters. The reaction uses peroxy acids or peracids and is often catalyzed by acid. The reaction is named after its pioneers, Adolf von Baeyer and Victor Villiger. The reaction is achieved by a wide range of peracids such as m-chloroperoxybenzoic acid (mCPBA), perbenzoic acid (C6H5COOOH), peracetic acid (CH3COOOH), hydrogen peroxide (H2O2), and tert-butyl hydroperoxide (t-BuOOH).
The carbonyl center is...
The carbonyl center is...
4.3K
01:15Acid-Catalyzed Aldol Addition Reaction
2.7K
The aldol reaction of a ketone under acidic conditions successfully forms an unsaturated carbonyl as the final product instead of an aldol. The acid-catalyzed aldol reaction is depicted in Figure 1.
2.7K
02:17Reduction of Alkenes: Asymmetric Catalytic Hydrogenation
3.4K
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...
3.4K