Chemistry Organic Reactions

# Chemistry Organic Reactions

## 1. Nucleophilic Substitution
- **SN1**: Two-step process, carbocation intermediate, rate = k[Substrate]. Favors polar protic solvents and tertiary substrates.
- **SN2**: Concerted single-step, inversion of configuration (Walden inversion), rate = k[Substrate][Nucleophile]. Favors polar aprotic solvents and primary/methyl substrates.

## 2. Elimination Reactions
- **E1**: Carbocation intermediate, Zaitsev product favored (more substituted alkene). Competing with SN1.
- **E2**: Concerted, requires anti-periplanar geometry. Strong base required. Follows Zaitsev’s rule unless sterically hindered (Hofmann product).

## 3. Addition Reactions
- **EA (Electrophilic Addition)**: Addition of HX/X2 to alkenes. Markovnikov's rule dictates regioselectivity via most stable carbocation intermediate.
- **SA (Nucleophilic Addition)**: Primarily on carbonyls (aldehydes/ketones). Grignard reagents, hydride reductions (NaBH4/LiAlH4).

## 4. Aromatic Substitution (AR)
- **Electrophilic Aromatic Substitution (EAS)**: Nitration, Sulfonation, Halogenation, Friedel-Crafts Alkylation/Acylation. Directing effects: Ortho/Para-directors (activating) vs. Meta-directors (deactivating).

## 5. Radical Chemistry (SR)
- **Free Radical Substitution**: Initiation, Propagation, Termination stages. Halogenation of alkanes (UV light/heat). Selectivity: 3° > 2° > 1° radicals.