Hello Montgomery! Dr. Schindler welcomes Montgomery to the Fire Nation! Over the years she has mastered the art of alkene metathesis, and she is willing to share this art with him for the price of his loyalty.

This step of the reaction proceeds by alkene metathesis. The starting materials are an alkene (attached to our starting material, represented by the R-group) and the Ruthenium catalyst. Together, they form a four membered intermediate and an ethene byproduct. An alkene attached to a 5 carbon chain with an OTBDPS group is then reacted again through alkene metathesis to be added to the starting material through another four membered intermediate. The Ruthenium catalyst is reformed by the second alkene metathesis.

Click on this link for a tutorial of alkene metathesis!