Studies On The Intramolecular Aerobic Friedel–crafts Acylation Reaction Of Benzoyacetone Derivatives

Friedel–Crafts reaction is one of the most common reactions of aromatic compounds. It has been widely used in the synthesis of small organic molecules and applied to the development of drug or macromolecular polymerization etc. Friedel–Crafts reaction mainly includes Friedel–Crafts alkylation reaction and Friedel–Crafts acylation reaction. In Friedel–Crafts acylation reactions, the acylation of acetophenones is difficult duing to the electron-deficient nature of the aryl rings. With the development of Friedel–Crafts acylation reaction, chemists have tried to use super acid etc to activate the electron-deficient aromatics to achieve Friedel–Crafts acylation reaction, but such methods are rarely reported.In addition, transition-metal-catalyzed oxidation reaction plays an important role in organic synthesis. However, the catalysts used are often noble metals such as Pd, Au, Rh, Ir etc, and the oxidants are often metal oxides such as Ag2 O, NiCl2 or benzoquinone, PhI(OAc)2, K2S2O8 and so on, which are not environment-friendly. With the promotion and development of green chemistry, the selection of the cheap metal with low toxicity(such as Fe, Cu, etc) and green oxidants(such as oxygen, etc) to realize the green oxidation reactions become more and more important. Their applications in the formation of carbon-carbon bonds and carbon-heteroatom bonds are also urgent requirement for laboratory and industrial synthesis. And it’s a great challenge to apply such green oxidation reactions to Friedel–Crafts acylation reaction of electron-deficient aromatics to construct new carbon-carbon bonds or carbon cycles.Our group has long been engaged in ketene dithioacetal chemistry. Various carbo/hetero-cycles have been produced from ketene dithioacetals. In this thesis, a remarkable facile intramolecular ortho-acylation of electron-deficient aromatics aryl ketones was developed for the first time from simple and accessible α-acetyl ketene dithioacetals, with molecular oxygen as the green oxidant. Naphthoquinones, 1, 2-indanediones and 1, 3-indandiones could be easily produced from this reaction. The structures of the products have been verified by NMR spectra, high-resolution mass spectra and single crystal analyses. At the same time, the mechanism of this novel reaction has also been investigated in details.