Friedel-Crafts Cyclization And Dearomatization Reactions Of Pyrroles And Indoles

This thesis mainly focuses on the development of Friedel-Crafts cyclization and dearomatization reactions of pyrroles and indoles taking advantage of their versatile reactivity.In the first part, we realized olefin cross-metathesis/intramolecular asymmetric Friedel-Crafts type cascade reaction of pyrrole derivatives and enones in the presence of Ru complex (Zhan-IB) and chiral phosphoric acid. This sequential catalysis provides a straight forward access to polycyclic pyrrole, a popular structural core in biologically interesting natural products and Pharmaceuticals from readily available starting materials.In the second part, dearomatization reaction of substituted pyrroles with α,β-unsaturated enones was realized in the presence of silica gel, which is inexpensive, readily available and nontoxic. This methodology features high efficiency and mild reaction conditions. Interestingly, the reactions worked smoothly with good regioselectivity when the unsymmetrical tri-substituted pyrroles were used. It is noteworthy that this is the first example on dearomatization reaction of pyrroles under metal-free conditions.In the third part, chiral phosphoric acid-catalyzed intramolecular asymmetric Friedel-Crafts reaction of indoles was achieved. This methodology provides a novel route for the synthesis of spiroindolenine skeletons in high yields and excellent enantio selectivity.