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 Bergman Cycloaromatization Reaction

Cascade Reactions

The Diels-Alder Reaction

Electrocyclic Reactions

Glycosidation

The Manzamine Synthetic Problem

Metathesis Reactions

Olefination Reactions

Pericyclic Reactions

Protecting Groups

The Quinine Synthetic Problem

Radical Reactions (Part 1)

Radical Reactions (Part 2)

The Strychnine Synthetic Problem

C-H Functionalization Lecture