Studies Of Lewis Acid Catalyzed Tandem Acylation-Nazarov Cyclization Reaction And Its Application In Organic Synthesis

In synthetic organic chemistry, cyclopentenones occupy a very important position. The ring struture is present in many natural products and interesting drug targets. Moreover, cyclopentenone is a valuable precursor for the synthesis of compounds containg a cyclopentane units. The synthesis of substituted cyclopentenones is always the focus of intensive synthetic efforts.Nazarov cyclization is a4π electrocyclic process through which a new carbon-carbon bond can be formed. It is an acid-catalyzed process. Nazarov cyclization is an important method for the synthesis of cyclopentenone moiety with stereogenic centers. In recent years, it plays a key role in total syntheses of complex natural products, as well as pHarmaceutical intermediates. The transformation have received tremendous attention in the field of organic synthesis.Tandem reaction is an important direction of the development of modern chemistry. It refers that the intermediates of first step directly involved in the next step of the reaction. Two steps of the reaction are mergered into one. This kind of reaction saves the purification process between two steps. It not only improves isolated yield but also friendly with environment. It has a vital significance.Our research is about reactions between α,β-unsaturated acid and aromatic ring. In the presence of trifluoroacetic anhydride and lewis acid, unsaturated carboxylic acids and aromatic compounds produce acylate, followed by Nazarov cyclization to form cylcopenta[b]aromatic. Ethyl malonic acid and formaldehyde can preparation α,β-unsaturated acid which can react with aromatic compounds to get cyclopentenones.