Oxidative or metal-mediated cyclization approaches to carbocycles and heterocycles

Abstract

A method for preparation of bicyclic aromatic orthoesters from the corresponding aldehydes via DDQ-mediated oxidative cyclization is described in chapter 1 of the thesis, the intermediate in our method is similar as the one which is impossible to be generated from carboxylate acid derivatives and alcohols directly. In chapter 2, a new strategy for the aromatic C–H bond functionalization is described. α-Tetralone could be oxidatively synthesized from the corresponding acylsilane with ethyl iodoacetate. Direct acylation of aromatic ring with acylsilane was achieved in the absence of strong Lewis acid or transition-metal. Finally, a W(CO)6-mediated intramolecular cyclization reaction from o-alkynylphenyl derivatives to afford 7-membered nitrogen-containing heterocyclic compounds 3,1-benzoxazepines is depicted. This method provided us a simple way to construct 7-membered heterocycles efficiently and regioselectively.