The following presentations have all been used to teach modern synthetic reactions in my graduate level courses, and present examples of reactions primarily in the context of natural product total synthesis.  Although there is no verbal play-by-play for these lectures, hopefully they will serve as helpful sources of information.

The [3+2] Cycloaddition Reaction

The Claisen Rearrangement

The Cope Rearrangement

The Colchicine Synthetic Problem

The Diels–Alder Reaction (Part 1)

The Diels–Alder Reaction (Part 2)

Electrocyclic Reactions

Glycosidation

The Manzamine Synthetic Problem

Metathesis Reactions

Olefination Reactions

Protecting Groups

Radical Reactions (Part 1)

Radical Reactions (Part 2)

Rearrangements

Ring Expansions/Contractions

C-H Functionalization Lecture