Basics in Organic Reactions Mechanisms
In organic chemistry, the mechanism of an organic reaction is defined as a complete step-by-step explanation of how a reaction of organic compounds happens. A completely detailed mechanism would relate the first structure of the reactants with the last structure of the products and would represent changes in structure and energy all through the reaction step.
Heterolytic Bond Breaking
Heterolytic bond breaking is also known as heterolysis or heterolytic fission or ionic fission. It is defined as breaking of a covalent bond between two different atoms in which one atom gains both of the shared pair of electrons. The atom that gains both electrons is more electronegative than the other atom in covalent bond. The energy needed for heterolytic fission is called as heterolytic bond dissociation energy.
Polar Aprotic Solvent
Solvents that are chemically polar in nature and are not capable of hydrogen bonding (implying that a hydrogen atom directly linked with an electronegative atom is not found) are referred to as polar aprotic solvents. Some commonly used polar aprotic solvents are acetone, DMF, acetonitrile, DMSO, etc.
Oxygen Nucleophiles
Oxygen being an electron rich species with a lone pair electron, can act as a good nucleophile. Typically, oxygen nucleophiles can be found in these compounds- water, hydroxides and alcohols.
Carbon Nucleophiles
We are aware that carbon belongs to group IV and hence does not possess any lone pair of electrons. Implying that neutral carbon is not a nucleophile then how is carbon going to be nucleophilic? The answer to this is that when a carbon atom is attached to a metal (can be seen in the case of organometallic compounds), the metal atom develops a partial positive charge and carbon develops a partial negative charge, hence making carbon nucleophilic.
Please draw the curved arrows to indicate the flow of electrons in the reactions below, and please draw the products formed
![### Chemical Reactions of Methyl Groups
The image depicts two different chemical reactions involving methyl groups (\( \mathrm{CH_3} \)) and shows the interactions of these groups with other elements.
#### Reaction 1: Interaction of Methoxide and Hydrogen
\[ \mathrm{CH_3O^- + H^+ \rightarrow} \]
- **Reactants**:
- **Methoxide Ion (\( \mathrm{CH_3O^-} \))**: This molecule contains a negatively charged oxygen with two lone pairs of electrons, denoted by the dots around the oxygen atom.
- **Hydrogen Ion (\( \mathrm{H^+} \))**: A positively charged hydrogen ion.
- **Explanation**:
- The negative charge on the oxygen in methoxide indicates an electron-rich site that can interact with positively charged species.
- The positively charged hydrogen ion (\( \mathrm{H^+} \)) acts as an electron-poor species.
- An arrow pointing to the right suggests a forward chemical reaction, implying that the methoxide ion and hydrogen ion will react to form a product.
#### Reaction 2: Interaction of Trimethylamine and Hydrochloric Acid
\[ \mathrm{(CH_3)_3N + HCl \rightarrow} \]
- **Reactants**:
- **Trimethylamine (\( \mathrm{(CH_3)_3N} \))**: This molecule includes a nitrogen atom bonded to three methyl groups (\( \mathrm{CH_3} \)). The nitrogen has a lone pair of electrons and a formal positive charge.
- **Hydrochloric Acid (\( \mathrm{HCl} \))**: A molecule composed of hydrogen and chlorine. The chlorine atom has three lone pairs of electrons.
- **Explanation**:
- The nitrogen in trimethylamine possesses a lone pair, making it an electron-rich site, despite the positive formal charge.
- Hydrochloric acid can donate a proton (\( \mathrm{H^+} \)) from the hydrogen atom, rendering the chlorine atom an electron-rich species.
- As indicated by the rightward arrow, the trimethylamine and hydrochloric acid will react, likely forming an ammonium ion (\( \mathrm{(CH_3)_3NH^+} \)) and a chloride ion (\( \mathrm{Cl^-} \)).
These reactions exempl](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2F5d8bd2a3-7f1c-4a1c-96e1-cb3fd44cae00%2F9b6bb4a6-d527-4737-b500-829880beb3c4%2Fxuctnsr_processed.png&w=3840&q=75)
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