Synthesis Of Polysubstituded Indenes Via Iron-Catalyzed Intramolecular Friedel-Crafts Cyclization

In the thesis, polysubstituted indene derivatives were prepared in moderate to excellent yield by FeCl₃·6H₂O-catalyzed intramolecular Friedel-Crafts cyclization of sulfonyl-containing tetrasubstituted allylic alcohols. The C-1 alkylation of the obtained 1H-indene with halohydro- carbons were further investigated. The thesis consists of the following two parts:Firstly, the FeCl₃·6H₂O-catalyzed intramolecular Friedel-Crafts cyclization of allylic alcohols were investigated. FeCl₃·6H₂O-Catalyzed intramolecular Friedel-Crafts cyclization of sulfonyl-containing allylic alcohols proceeded smooyhly in CH2Cl2 at room temperature. Sulfonyl-containing indenes were obtained in good to nearly quantitative yield. All the products were characterized by 1H NMR, 13C NMR, IR and HRMS. The molecular structures of 1,3-diphenyl- 2-tosyl-1H-indene (2a), 3-butyl-1-(4-chloro-phenyl)-tosyl-1H-indene (2j) and 6-methyl-1,3- diphenyl-2-tosyl-1H-indene (2q) were determined by X-ray diffraction analysis.Secondly, we further investigated the synthesis of 1,1,2,3- tetrasubstituted indenes. 1,1,2,3-Tetrasubstituted indenes were synthesized in high yield by the reaction of compound 2a with Grignard reagent and its further coupling with halohydrocarbon catalyzed by Ni(PPh3)2Cl2. The products were characterized by 1H NMR,13C NMR,IR and HRMS.The iron trichloride-catalyzed Friedel-Crafts cyclization reaction of allylic alcohols provides a new method for the synthesis of polysubstituted indene derivatives. The reaction has the advantages of easily available starting materials, inexpensive and environmentally friendly catalyst, simple manipulation, mild reaction conditions, water as the only theoretical byproduct and the high efficiency.