Synthetic Studies on Natural Isocoumarins and Isocarbostyril Derivatives Having an Alkyl Substituent at the 3-Position: Total Synthesis of Scoparines A and B, and Ruprechstyril
Two isocoumarins, scoparines A and B, having n-propyl group at the 3-position, and a new isocarbostynl, ruprechstynl, beanng n-pentyl substituent at the 3-position were synthesized via Sonogashira coupling of the corresponding aromatic halides and alkynes, followed by regioselective 6-endo-dig cyclization.