Organic Chemistry Reaction Intermediates

Alkyl groups (like CH3) attached to benzene rings are electron-donating groups known as +R groups.

The +R effect in alkyl benzenes makes them undergo electrophilic aromatic substitution (EAS) reactions preferentially at the ortho and para positions.

The +R effect of alkyl groups strengthens the benzene ring, making it more reactive towards EAS. Hence, alkyl benzenes are activating groups.

The electron-donating ability of alkyl groups depends on the number of hydrogens attached to the carbon atom adjacent to the benzene ring (alpha carbon).

Hyperconjugation is the delocalization of electrons from C-H sigma bonds to the empty p-orbital of the benzene ring.

Groups like -CX3 (e.g., -CF3) are meta directing and deactivating towards EAS.

The meta directing effect of -CX3 groups can be explained by the inductive effect, where electron density is withdrawn from the benzene ring.

The -CX3 groups are deactivating because they make the benzene ring less susceptible to attack by electrophiles.

Nitrogen compounds similar to carbenes with a lone pair of electrons on nitrogen.

Nitrenes can be formed through the decomposition of azides in the presence of heat or light.

Neutral covalent compounds with a complete octet on the central atom, at least one lone pair of electrons, and non-electronegative atoms attached are classified as neutral nucleophiles.

Amines (R-NH2, R2NH, R3N) are examples of nitrogen-containing nucleophiles.

Attackers can be classified into two main groups: neutral nucleophiles and electrophiles.

The fission of a substrate molecule to create centers of high or low electron density is influenced by attacking reagents.

Attacking reagents can be either electron-rich (nucleophiles) or electron-deficient (electrophiles).

These are species that attack electron-deficient sites.

A type of bond breaking where each atom involved receives one electron from the shared pair, resulting in the formation of neutral species with an unpaired electron known as free radicals.

A species formed by homolytic bond fission, characterized by having an unpaired electron, making it neutral and highly reactive.

The process of breaking a covalent bond where one atom receives both electrons from the shared pair, resulting in the formation of two ions with opposite charges.

A positively charged ion formed by heterolytic bond fission, where the carbon atom has only six electrons in its valence shell.

A negatively charged ion formed by heterolytic bond fission, where the carbon atom has an extra pair of electrons in its valence shell.

A neutral, divalent species with two unshared electrons, formed from a carbon atom with a pair of free electrons.

A very unstable species where the carbon atoms involved are bonded by a triple bond, but one of the bonds is strained and readily breaks.

A highly reactive species with a nitrogen atom containing an unpaired electron, capable of undergoing a variety of reactions.

Involving substitution at the alpha carbon atom with respect to the double bond.

A reaction where a molecule gains two sigma (σ) bonds and loses one pi (π) bond, often resulting in a more stable product.

A type of reaction where an electrophile attacks an alkene, leading to the formation of a new carbon-carbon bond.

A halogenation reaction using N-bromosuccinimide (NBS) as a selective brominating agent, mainly targeting allylic positions.

A reaction where an alkyl halide reacts with metallic sodium to form alkanes, often involving a free radical mechanism.

Replacing one atom or group in a molecule with another atom or group.

Adding atoms or groups across a double or triple bond.

Removing atoms or groups from a molecule, typically forming a double or triple bond.

Rearranging the atoms within a molecule to create a new structure.

The strength of an acid is directly related to the stability of its conjugate base.

Nucleophiles are electron-rich species that attack electron-deficient centers.

Groups that can easily leave a molecule during a reaction, often as anions.

The strength of a nucleophile depends on its ability to donate electrons. More basic nucleophiles are generally better.

The ability of a group to leave a molecule during a reaction is inversely related to its basicity.

Organic reactions are classified into four main types: substitution, addition, elimination, and rearrangement.

SN2 reactions involve a one-step process where the nucleophile attacks the substrate from the back side, resulting in an inversion of configuration.

SN1 reactions proceed through a two-step mechanism. The first step involves the formation of a carbocation intermediate, which is then attacked by the nucleophile.

SN2 reactions are second-order reactions, meaning the rate depends on the concentrations of both the substrate and the nucleophile.

SN1 reactions are first-order reactions, meaning the rate depends only on the concentration of the substrate.

SN2 reactions are bimolecular, meaning the slow step involves two molecules (substrate and nucleophile).

SN1 reactions are unimolecular, meaning the slow step involves only one molecule (the substrate).

In SN2 reactions, the nucleophile attacks from the back side of the substrate, leading to complete inversion of configuration.

In SN1 reactions, both inversion and retention of configuration can occur. This is because the nucleophile can attack the carbocation from either side.