Explore the mechanisms of acyl insertions and alpha-carbon reactivity in this 49-minute lecture from Yale University's Freshman Organic Chemistry II course. Discover how nucleophilic atoms with good leaving groups can attack carbonyl groups, leading to the migration of adjacent R groups and the insertion of O, NH, or CH2 groups into acyl bonds. Examine the stereospecificity of the Beckmann rearrangement of oximes and understand the relative migratory aptitudes of formally anionic groups. Delve into the acid dissociation of alpha-protons to form enolates and enols, granting nucleophilic reactivity to alpha-carbons under both basic and acidic conditions. Learn about H/D exchange, racemization, halogenation, and alkylation of alpha-carbons through detailed explanations and examples.