Stereoselective Construction Of Chlorinated And Brominated Indanone Derivatives

Halocarbon products are useful chemical intermediates, serving as branch points in the synthesis of numerous functionalized molecules, and having close in touch with agricultures and enviroments. Complex operation, low yields and the separation of intermediates are disadvantageous for constructing halocarbon products having complicated structures. So it is important that finding a method to prepare halocarbon products efficiently and environmentally.Cascade reaction can form several covalent bonds in one pot, it is an efficient synthesis strategy of constructing complicated organic compounds economically and frequently. And cascade reaction has become a new field in recent years.In this paper, a one-pot three component cascade reaction proceeds by way of a Lewis acid-catalyzed Knoevenagel condensation/Nazarov cyclization /electrophilic chlorination and bromination sequence to afford chlorinated and brominated 1-indanone derivatives in moderate to good yields with high diastereoselectivities.This is a new reaction, the effect of solvent polarity, temperature, time and reaction scale has been examined, which was taken for optimization system. Good results were observed. All products were unknown compounds and their structures have been determined by IR, 1H NMR, 13C NMR, MS and element analysis. X-ray diffraction gave the crystal structure of 2-Chloro-2-methoxyl-3-phenyl-1-indanone, which elucidated that chlorination occurs trans to the R group of Nazarov cyclization intermediate. So cascade reaction is an efficient method to construct halocarbon products.