Molecular diversity of cycloaddition reactions of the functionalized pyridinium salts with 3-phenacylideneoxindoles

The cycloaddition reactions of a series of functionalized pyridinium salts, which were generated from reaction of pyridine with active alkyl halides such as p-nitrobenzyl bromide, N,N-diethyl chloroacetamide and phenacyl bromides with 3-phenacylideneoxindoles in the presence of triethylamine showed very interesting molecular diversities. A series of the functionalized spiro[cyclopropane-1,3'-indolines], and 3-furan-3(2H)-ylidene)indolin-2-ones were successfully prepared depending upon the structures of the pyridinium salts and reaction conditions. The regioselectivity and stereoselectivity of the reactions as well as reaction mechanisms were briefly discussed. (C) 2013 Elsevier Ltd. All rights reserved.