Mechanistic Steps in Organic Chemistry

Vocabulary flashcards detailing common organic chemistry reaction steps, descriptions of what occurs, and corresponding curved-arrow electron movements.

Proton transfer

A mechanism step where a base takes an $H$ from an acid. The curved arrows show the base lone pair moving to $H$ and the $H-A$ bond moving to $A$.

Nucleophilic addition

A mechanism step where a nucleophile attacks a $C=O$ group. The curved arrows show the nucleophile moving to the carbonyl $C$ and the $C=O$ $\pi$ bond moving to $O$.

Nucleophilic elimination

A mechanism step where a tetrahedral intermediate re-forms $C=O$ and kicks out a leaving group. The curved arrows show an $O^-$ lone pair moving to form $C=O$ and the $C-LG$ bond moving to $LG$.

Heterolysis

A mechanism step where a bond breaks and both electrons go to one atom. The curved arrow shows the bond moving to the leaving group.

Coordination (electrophilic addition)

A mechanism step where a nucleophile or $\pi$ bond forms a bond to a cation. The curved arrow shows a lone pair or $\pi$ bond moving to the cationic atom.

Bimolecular nucleophilic substitution

A mechanism step where a nucleophile attacks as the leaving group leaves, in one step. The curved arrows show the nucleophile moving to carbon and the $C-LG$ bond moving to $LG$.

Carbocation rearrangement

A mechanism step where a group shifts to the cation and the charge moves. The curved arrow shows a shifting bond ($C-H$ or $C-C$) moving to the cationic carbon.

Conjugate addition

A mechanism step where a nucleophile adds to the alkene carbon of an enone. The curved arrows show the nucleophile moving to alkene $C$, the alkene $\pi$ bond moving to the next bond, and the $C=O$ $\pi$ bond moving to $O^-$.