Haloalkanes to Amines: NCERT Chemistry

• Gratitude is expressed to the audience for patience.
• The audience's dedication to learning is acknowledged.
• The audience's enthusiasm inspires the speaker.
• The speaker recalls the "10 Challenge" and the audience's support.
• Sessions will target board exams and JEE preparation.
• Focus is given to reasoning-based chemistry questions from the last board exam.
• The teaching strategy benefits both board and JEE exams.
• The first class covers theory and basics.
• Topics from Haloalkanes to Amines from NCERT are to be covered.
• All reactions, reagents, and named reactions will be revised and understood.
• The second class focuses on problem-solving with board exam examples.
• "Aarambh" event on March 1st is highlighted.
• The event is the biggest educational festival with prizes and surprises.
• Listening to speakers and taking opportunities at the event is advised.

Basics to be Covered

• Acidity and basicity concepts will be covered.
• Transition to Haloalkanes.
• Focus on understanding reagents and name reactions.

Solving

• The second session emphasizes problem-solving.
• Board exam papers are used to demonstrate reasoning.

Apic Educational Festival: Aarambh Details

• Date: March 1st.
• Targeted at: IIT-JEE, NEET-UG, and Foundation students.
• Mega rewards are included.
• Time: 7 PM to 9 PM.
• Attendees should enable notifications.

Acidity and Basicity

• Understanding acidity involves +I, -I, +M, -M, and hyperconjugation effects.
• Assumes no prior knowledge of the concepts.

Inductive Effect

• Affects sigma electrons within a bond.
• It is the permanent polarization of electrons in a sigma bond.
• It is based on electronegativity differences between atoms.
• The electronegativity differences should be evaluated between atoms.
• Comparison is made between the group's first atom and an sp3 carbon atom in a saturated hydrocarbon chain.
• Higher electronegativity indicates a -I group pulling electrons.
• Effects on sigma electrons are impermanent.

Cool and Food Concept (KFC) related to Electronegativity

• Second-period atom with a negative charge has less electronegativity than sp3 carbon.
• Examples: C-, O-, and N- have lower electronegativity than sp3 carbon.
• A minus group with a negative charge (+I) acts as a donor.
• Inductive effects generally fade after the second or third carbon, making it weak.
• Significant in some usecases, such as relative acidity differences.

Examples of Inductive Effect Groups

• CH2+ is electron deficient (-I group).
• CH2- with a negative charge is a +I group.
• N+ is extremely electron deficient (-I group).
• NH2 is -I due to nitrogen's electronegativity.
• N- is +I because of charge.
• C2H5 (ethyl) is an alkyl +I group.

Alkyl Groups and Electron Donation

• Alkyl groups like methyl donate electrons due to hydrogen.
• Alkyl groups gain a delta negative charge.
• Alkyl group donates electrons when combined with neutral carbon.
• 1°, 2°, and 3° carbons donate better than methyl.

Isotope Effects on Electron Donation

• Heavier isotopes are better sigma electron donors.
• Lighter isotopes facilitate easier bond breakage for hyperconjugation.

Intermediates

• Intermediates are short-lived and formed/consumed during a reaction mechanism.

Types of Intermediates

• Includes Carbocation, Carbanion, Free radical, Nitrene, and Carbene.
• Carbene occurs in Reimer-Tiemann reaction (RTR), and nitrene in Hofmann bromamide reaction (HBR).

Carbocation

• Three bonds and a vacant orbital.
• Six shared electrons.
• Carbon's only intermediate with a vacant orbital.
• Acts as a Lewis acid (+).
• Higher electronegativity than sp3 carbon gives it -I and -M effects.

Stability of Species

• Charge minimization, size optimization, and energy reduction are crucial for maximum stability.

Carbocation Stabilization

• Stabilized by electron-donating groups like +M, +H, and +I.
• Greater electron donation results in more stability.

Carbanion

• Three bonds, a negative charge, and a lone pair.
• Every negative charge has a hidden lone pair.
• It is an eight-electron and electron-rich species.
• Behaves as a Lewis base.
• Exhibits +I and +M effects.
• Stabilized by -I and -M groups.

Free Radical

• Has seven electrons.
• Electron deficient species.
• Shows -I behavior.
• Behaves as a Lewis acid.
• Stabilized by electron-donating groups (+H, +I, etc.).

Mesomeric Effect

• Resonance caused by interaction between a lone pair and pi bond, or alternating pi bonds.
• Based on pi electron density.
• Pi electron density order: Negative charge > Lone pair > Pi bond > Positive charge.
• High electron density species are pi electron donors.
• C=C is dual natured.

Key Steps to Understanding +M and -M (Mesomeric Effect)

• Define "First Atom of the Group".
• Where are vacant orbitals found?
• Can vacant orbitals be created?

First Atom Of The Group

• In OH, oxygen is the first atom.
• In NH2, nitrogen is the first atom.

Native Vacant Orbitals

• Third-period elements have d-orbitals (e.g. sodium).
• Every group element will be a pi electron acceptor (-M).
• Second-period elements (Boron, carbon with a positive charge (Carbocations), and nitrogen if it has two bonds and a lone payer will all be positive.

Vacant Orbital Creation

• Vacant orbitals can be created in A=B structures where B is more electronegative than A.

Identifying Groups That Show +M, -M, +I, -I

• Carbonyl is -M and -I.
• Negative charges make groups +M and +I.
• Nitrogens with a single bond and a double bond exhibit +M and -M.
• Alkyl groups (C2H5) are +I & halogens are -I.
• Sp-hybridized carbon can be a -I with Acetylenes/triple bonds all +M.
• N2+ creates vacant orbitals similar to NO2, exhibiting only -M and -I.

Acidity of Carboxylic Acids

• Anion stability matters.
• Electron withdrawing groups increase stability.

Basicity Measurement

• Acid strength is judged through the Pka value
  • Higher means more basic, lower means more acidic
• Carbon-chains are generally more likely to be sp3 hybridized than sp2 or sp
• O-H means more acidic/releasing.

Hyperconjugation

• Involved delocalization of carbon molecules by showing bonds.
• Requires the formation of Conjective systems from parallel Z atomic fields.

Conjugated system

• It is a route for the easy transfer of pi molecules through sp2 Atomic structure.
• Look for sp2 hybridised atomic structures attached to multiple bonds.
• Look for lone pairs attached to multiple bonding atoms (said to be "p z").
• Positively charged systems mean vacant orbitals.

Hyper-Conjugation Steps:

• Find the alpha molecules attached to the hybridised carbon
• Show the splitting of the Carbon Hydrogen bond into a positive and split the hybridization.
• Show the new hybridized pi alignment.
• Move any negative molecules with loan pairings in alternating position.

Acidity

• Acid-base universal rule of stability
• To stabilize by minimizing change, especially near high volumes.
• Size has an inverse impact.
• If something has too much heat, it may become explosive rather than stable.

Mesomers

• For best results, Mesomers should be placed in between two conjugate molecules.
• Positive charges attract with empty spaces.

Carbocation Stability

• More alpha connections to positive charge increase stability.
• Positive charge is only stable at ortho and para locations.

Intermediated Stability for Reactions

• Reactions move towards the most stable intermediate before the next reaction occurs.

Alkyl Halides

• Important for substitution, bond-breaking, etc.
• Useful base knowledge for breaking down more complex reagents.

Good Leaving Groups

• I-, Br- and Cl- are increasingly worse at breaking bonds.
• More stable ions leave more readily.

Good Nucleophile:

• Tendency for carbon to bond.
• Increased stability from carbon bond formation tends to occur when paired with Anion or Cation

Strong Bases vs Weak Bases:

• Strong bases form the environment for two or more elements to form.
• Where both are present vs weak bases.
• Most are E-2 and not SN-2. Some have some SN-2 properties.

The Magic Chart

• Consider all cases cautiously.
• Carbon in a 3-way bond needs Sp-2 to hybridize.
• SN's favor stability between 1, 2, and 3 chain formations.
• Understanding the relationships between hybridization and carbon chain formations, reagent reactions are intuitive.

SN1:

• Based on carbocation reaction.
• Stronger with bulker groups (3>,2>,1>0)
• SN1 reactions have multiple reactions as the Nu molecule comes from and can be inverted for steriometric reasons making some D and L mixtures.
• Always more inverted molecules.

Sn2:

• Occurs in the opposite rotation to SN1
• The higher energy, the less stable the species
• If the original product was sp3 the new item formed if there is a chirality will be inverted
• Inversion is one of the most reliable stereochemistries.

E1:

• The same side of the process where the removal and addition occurs.
• But only in the presence of heat, which needs to be in a liquid state.
• With H20
• Without the liquid state there no SN-1

Key things to Consider when Using Magic-Chart

• The leaving groups power
• The type of reagent
• Electrophile?
• Bulky?
• Whether anything will drive the change.

Reagents Key Notes by Type:

• Grignard + Carbonil's: Carbon Bonds break with each reaction
• Grignards can also be very stable and unreactive
• H2Pdbaso4: Opens 2 bonds where it attaches.
• Li Nh3 or Na Nh3 Will repel to cause a "trans- alkane" state
• KMO4: Splits and fully oxidizes Carbon bonds.
• Reagents with acid: convert into Alconels.
• ZnOH: Used to convert alcohol to ALkane

SN1 and SN2 Exceptions:

• No un saturated Carbons.
• No Bird Positions
• No Neon position of sp3 as there won't be SN1 OR SN2

Named Molecule reactions

• Require rote memorization.
• Primarily identified by names to products/reagents
• All share base features from the processes and reagents studied.

Williamson Ether Synthesis Reagents

• Must be high in basicity
• High Heat Sensitivity

Halogenation

• Very often occurs in acid
• Ions need to be stabilized to transfer/gain electrons

Alcohol to Acolines

• Moves alcohol to a single chain
• Acts as a catalyst and doesn’t add new molecules.
• If Alkein added:
• Carbon is added in 2:1 ratio.
• Alklines bind reactions on the same spot and may use this.
• H-G addition occurs and then alkane if HG is added, it initiates a chain reaction.

Hydro-boration

• HOH added into OH location, with less markoff control (IE location next to another part).
• Can reduce 3 HOH molecules at once

Reductions

• Often require heat for full release.
• Double-check for easy oxygen removals.
• End goal is to oxidize the reagent while reducing the starting molecule.

Reimer Tiemen Reaction

• Converts phenol to salicylaldehyde using chloroform, base, then H+.
• A strong base stabilizes the hybridization of intermediate molecules
• Where H tends to be is indicative of where it lands.