PHD
  1. Inorganic chemistry  1.1. Coordination chemistry  1.1.1. Ligand field theory  1.1.2. Crystal field theory  1.1.3. Molecular Orbital Theory for Coordination Compounds  1.1.4. Stability of Coordination Compounds  1.1.5. Electronic spectra of coordination compounds  1.1.6. Isomerism in Coordination Compounds  1.1.7. Kinetics and mechanism of coordination reactions  1.2. Organometallic Chemistry  1.2.1. Metal Carbonyls  1.2.2. Metal alkyl and aryl  1.2.3. Fischer and Schrock carbonaceans  1.2.4. Oxidative Addition and Reductive Elimination  1.2.5. Metal Hydrides  1.2.6. Catalysis by organometallic compounds  1.2.7. Metallocenes and Sandwich Complexes  1.2.8. CH activation  1.3. Solid state chemistry  1.3.1. Crystal structures and lattices  1.3.2. Band theory and electrical properties  1.3.3. Defects in the crystal  1.3.4. Synthesis of solid state materials  1.3.5. Magnetic and optical properties of solids  1.3.6. Superconductivity  1.3.7. Solid state ionics  1.4. Bio-inorganic chemistry  1.4.1. Metalloproteins and enzymes  1.4.2. Metal ion transport and storage  1.4.3. The role of metals in medicine  1.4.4. Bioinspired catalysis  1.4.5. Metal–DNA interactions  1.4.6. Metal Complexes in Medical Science  1.5. Lanthanides and Actinides  1.5.1. Electronic configuration and oxidation states in lanthanides and actinides  1.5.2. Spectral and Magnetic Properties in Lanthanides and Actinides  1.5.3. Separation and Extraction of Lanthanides and Actinides  1.5.4. Coordination chemistry of f-block elements  1.6. Main Group Chemistry  1.6.1. Chemistry of boron compounds  1.6.2. Chemistry of Silicon and Germanium Compounds  1.6.3. Chemistry of Phosphorus and Sulfur Compounds  1.6.4. Organosilicon chemistry  1.6.5. Noble Gas Chemistry
  2. Organic chemistry  2.1. Reaction mechanism  2.1.1. Nucleophilic substitution reactions  2.1.2. Electrophilic addition and substitution reactions  2.1.3. Elimination reactions  2.1.4. Rearrangement reactions  2.1.5. Radical reactions  2.1.6. Pericyclic Reactions  2.1.7. Photochemical reactions  2.2. Stereoscopic  2.2.1. Chirality and optical activity  2.2.2. Structural analysis  2.2.3. Stereoelectronic effects  2.2.4. Asymmetric synthesis  2.2.5. Dynamic Stereochemistry  2.3. Organometallic Chemistry in Organic Synthesis  2.3.1. Organolithium and organomagnesium reagents  2.3.2. Transition metal catalyzed coupling reactions  2.3.3. Palladium-catalyzed reactions  2.3.4. Olefin Metathesis  2.3.5. Gold and silver catalysis  2.4. Natural products chemistry  2.4.1. Alkaloids and terpenoids  2.4.2. Steroids and Flavonoids  2.4.3. Total synthesis of natural products  2.4.4. Biosynthesis of natural products  2.5. Supramolecular Chemistry  2.5.1. Host-Guest Chemistry  2.5.2. Self-assembly and molecular recognition  2.5.3. Supramolecular Catalysis  2.5.4. Molecular Machines
  3. Physical Chemistry  3.1. Thermodynamics  3.1.1. Laws of Thermodynamics  3.1.2. Chemical Potential and Equilibrium  3.1.3. Statistical thermodynamics  3.1.4. Non-equilibrium thermodynamics  3.2. Quantum Chemistry  3.2.1. Schrödinger equation and its applications  3.2.2. Molecular orbital theory  3.2.3. Density functional theory  3.2.4. Post-Hartree–Fock methods  3.3. Chemical kinetics  3.3.1. Reaction rate theory  3.3.2. Mechanism and rate laws  3.3.3. Catalysis and enzyme kinetics  3.3.4. Reaction dynamics  3.4. Spectroscopy and molecular structure  3.4.1. Infrared Spectroscopy  3.4.2. UV-visible spectroscopy  3.4.3. Nuclear Magnetic Resonance Spectroscopy  3.4.4. Mass Spectrometry  3.4.5. Raman Spectroscopy  3.5. Surface and Colloid Chemistry  3.5.1. Absorption and Catalysis  3.5.2. Surfactants and micelles  3.5.3. Colloidal Stability  3.5.4. Nanomaterials and Interfaces
  4. Analytical chemistry  4.1. Chromatography  4.1.1. Gas Chromatography  4.1.2. High Performance Liquid Chromatography  4.1.3. Thin Layer Chromatography  4.1.4. Ion Chromatography  4.2. Electroanalytical techniques  4.2.1. Voltammetry and Polarography  4.2.2. Conductometry and potentiometry  4.2.3. Colometry  4.3. Spectroscopic Methods  4.3.1. Atomic absorption spectroscopy  4.3.2. Fluorescence Spectroscopy  4.3.3. X-ray diffraction  4.3.4. Electron paramagnetic resonance spectroscopy  4.4. Chemometrics  4.4.1. Data processing and statistical methods  4.4.2. Multidisciplinary analysis  4.4.3. Machine Learning in Analytical Chemistry
  5. Theoretical and Computational Chemistry  5.1. Molecular dynamics simulation  5.2. Quantum chemistry methods  5.3. Computational drug design  5.4. Machine Learning in Chemistry  5.5. Ab initio molecular dynamics
  6. Biophysics and Medicinal Chemistry  6.1. Drug discovery and design  6.2. Enzyme kinetics and inhibition  6.3. Chemical biology approach  6.4. Protein-ligand interactions  6.5. Bioorthogonal chemistry
  7. Materials chemistry  7.1. Polymer chemistry  7.1.1. Polymerization mechanism  7.1.2. Functional Polymers  7.1.3. Biodegradable Polymer  7.1.4. Conducting and semiconducting polymers  7.2. Nano Chemistry  7.2.1. Nanoparticles and nanostructures  7.2.2. Carbon-based nanomaterials  7.2.3. Quantum dots  7.3. Energy and Environmental Chemistry  7.3.1. Battery and Fuel Cell Chemistry  7.3.2. Green chemistry and sustainable materials  7.3.3. Photocatalysis

PHD → Organic chemistry ↓


Organometallic Chemistry in Organic Synthesis


In organic chemistry, organometallic chemistry plays a vital role due to the unique reactivity and versatility of organometallic compounds. Introduction to organometallic compounds focuses on molecules containing at least one metal-to-carbon bond, where the metals can vary from main group elements to transition metals. These compounds have revolutionized synthetic methodologies, providing more efficient and selective routes to complex molecules.

What are organometallic compounds?

Organometallic compounds are molecules that contain a direct bond between a metal atom and a carbon atom. The metal atom can be from different groups in the periodic table, while the carbon can be part of different organic groups, such as alkyl, aryl or alkenyl groups.

Importance in organic synthesis

The role of organometallic chemistry in organic synthesis is significant, as these compounds can act as both nucleophiles and electrophiles. Their ability to engage in a variety of reactions such as cross-coupling, addition and metathesis has opened new avenues in the preparation of drugs, polymers and complex natural products.

Grignard reagent

Grignard reagents, generally denoted as RMgX (where R is an organic group and X is a halogen), are one of the most widely used organometallic reagents. These reagents are prepared by reacting alkyl or aryl halides with magnesium metal. A distinctive feature of Grignard reagents is their ability to react with electrophiles to form carbon-carbon bonds.

R-Br + Mg → RMgBr

Grignard reagents are nucleophilic and react readily with a variety of electrophiles such as carbonyl compounds. For example:

R-MgBr + R'-CHO → R-CH(OH)-R'
R-MgBr R'-CHO R-CH(OH)-R'

This illustration shows the process of converting a carbonyl group to an alcohol using the Grignard reagent.

Organolithium reagents

Organolithium reagents, denoted as RLi, are another class of organometallic compounds widely used in organic synthesis. They act as powerful bases and nucleophiles, playing a role similar to Grignard reagents but generally with higher reactivity.

Organolithium compounds can be prepared by the reaction of an alkyl halide with lithium:

2 R-Br + 2 Li → 2 RLi + Br2

The strong basic nature allows organolithium compounds to deprotonate a variety of substrates:

R-Li + HR' → RH + R'-Li

This reaction is useful for generating carbanions, which can subsequently be used for nucleophilic attacks on electrophiles.

Transition metal catalysts

Transition metals form the foundation of many catalytic cycles involved in complex organic transformations. Their ability to switch between different oxidation states, as well as the diversity of ligands they can coordinate with, make them ideal catalysts for a variety of reactions.

Cross-coupling reactions

Cross-coupling reactions are a group of methods where organometallic reagents are coupled with organic electrophiles in the presence of metal catalysts. One of the most prominent cross-coupling reactions is the Suzuki coupling, which couples organoboron compounds with halides.

RB(OH)2 + R'-X → RR' + BX + H2O

In this reaction, the palladium catalyst helps form a new carbon-carbon bond between two different organic groups.

Rb(OH)2 R'-X R-R'

This illustration shows the conversion possibility offered by Suzuki coupling using a transition metal catalyst.

Olefin metathesis

Olefin metathesis is a powerful reaction in which substituents around the double bond of an alkene are redistributed to form new olefins. Catalyzed by metal carbenes, this process is useful in the synthesis of polymers, pharmaceuticals, and petrochemicals.

R-CH=CH-R' + R''-CH=CH-R''' → R-CH=CH-R''' + R''-CH=CH-R'

Ruthenium-based catalysts often facilitate this process due to their robustness and functional group tolerance.

R-CH=CH-R' R''-CH=CH-R''' R-CH=CH-R''' R''-CH=CH-R'

Carbonylation reactions

Carbonylation reactions introduce carbon monoxide into organic substrates, providing an efficient route to carbonyl compounds. Organometallic reagents, particularly those involving nickel and palladium, facilitate these transformations.

A common example is the conversion of alkyl halides to carboxylic acids:

RX + CO + H2O → R-COOH + HX

The incorporation of CO in a controlled manner relies heavily on a catalytic cycle facilitated by transition metals.

Applications in drug development

Many pharmaceutical compounds involve complex molecular structures that are difficult to synthesize using conventional organic methods. Organometallic chemistry provides unique tools for selectively creating these molecules.

For example, the Pyrrola–Paar reaction, driven by a palladium catalyst, enables the construction of indole frameworks commonly found in many natural products and active pharmaceutical ingredients.

The future of organometallic chemistry

With advances in computational modeling and green chemistry, the future of organometallic chemistry looks promising. Researchers are focusing on developing more eco-friendly reagents and catalysts, reducing environmental impact and increasing reaction efficiency.

The integration of biocompatible metals and the discovery of new ligand structures will continue to expand the frontiers of organic synthesis.

Conclusion

Overall, organometallic chemistry is at the core of modern organic synthesis, providing unprecedented routes to create complex molecules with precision. Whether working with simple Grignard reagents at the lab bench or designing new transition metal catalyzed processes, the impact of organometallics spans a variety of fields, including pharmaceuticals, agriculture, and materials science.


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Organometallic Chemistry in Organic Synthesis

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