The formal synthesis of (+)-nakadomarin A was completed. The significant points of this synthesis are the highly stereoselective formation of the diazatricyclo[6.4.0.01,5]dodecane skeleton (A, B, and Drings) based on the Pauson−Khand reaction and novel furan ring (Cring) formation, using the vinyl residue of the Pauson−Khand product.