Study On Novel Generations Of Heteroaromatic O-Quinodimethanes (o-QDMs) And Their Diels-Alder Reactions

This dissertation mainly focused on the preparation of heteroaromatic o-Quinodimethanes (o-QDMs) and their Diels-Alder reactions. Two novel methods to construct heteroaromatic o-QDMs had been developed. In addition, the generated heteroaromatic o-QDMs could reacted with different dienophiles in situ via Diels-Alder reactions to afford various valuable heteropolycyclic compounds.1. A novel strategy to prepare furan-based o-QDMs catalyzed by the gold-mediated dehydrogenative heterocyclization of conjugated yne-eneones in the presence of pyridine N-oxide was developed. The generating furan-based o-QDMs were trapped by different dienophiles in situ to furnish various 2,3-furan-fused carbocycles. Furthermore, a novel furan dearomative Diels-Alder reaction was observed which could afford 2,3-dihydrofuran-fused carbocycles efficiently.2. Based on the research of furan-based o-QDMs, the metal catalyst combined with organocatalyst catalyzed tandem cyclization/asymmetric Diels-Alder reaction of conjugated yne-eneones and α,β-unsaturated aldehyde had been realized in high to excellent diastereo- and enantioselectivity.3. A novel method to construct indole-based o-QDMs was realized via either DDQ or BQ-mediated dehydrogenative reaction of 2-methyl-3-arylmethyl-indoles. The reactive intermediate (indole-based o-QDMs) could react with different dienophiles in situ to give synthetically valuable N-heterocycles such as tetrahydrocarbazoles, carbazoles, and carbazole quinone. More importantly, the carbazole quinone could be used in the synthesis of novel fused heteroacenes with potential applications in material science.