An intriguing stepwise diradical mechanism of the dimerization of the reactive intermediate (thiocarbonyl S-methanide) appearing in the reaction of phenyl selenophen-2-yl thioketone with diazomethane was studied by means of computational methods. The preferred formation of the unusual macroheterocycle, competitive with the 1,3-ring closure leading to a thiirane and the head-to-head dimerization...

Ferrocene derived P,S-heterodonor ligands were effectively used in AgOAc catalyzed asymmetric cycloaddition of azomethine ylides. The roles of planar chirality and electronic properties of the phosphorous substituents have been examined, and up to 93% ee was obtained. 2007 Elsevier Ltd. All rights reserved. The 1,3-dipolar cycloaddition reaction has become a powerful synthetic tool, providing a...

5-Substituted-4-thio-2'-deoxyuridine nucleosides have been chemically synthesized and studied by NMR and UV spectroscopy. The results have been analyzed and discussed in connection with the previous data. The imino proton signal and the carbon signal of the thiocarbonyl group in the 5-substituted-4-thio-2'-deoxyuridines were found to be at much lower field, offering a potential for monitoring t...

There exist three possible patterns for the reaction of cyclic 2-oxazolidinethione and 2-benzoxazolidinethione with arynes, namely (a) S-arylation, (b) N-arylation, and (c) aryne insertion into the thiocarbonyl group (C[double bond, length as m-dash]S). Our studies demonstrate that S-arylation wins out affording S-aryl dihydrooxazoles. In contrast, for related reactions of cyclic 2-benzoxazolin...

Abstract One-pot two sequential [3 + 2] cycloadditions of azomethine ylides with different dipolarophiles for diastereoselective synthesis spirooxindole pyrrolizidines are introduced. This one-pot involving five components generates a highly condensed ring system bearing seven stereocenters diastereoselectively. The new method has high pot, atom, and step economy. Only equivalents water release...