Nickel(II) chloride hexahydrate catalyzed reaction of aromatic aldehydes with 2-mercaptoethanol: formation of supramolecular helical assemblage of the product

Various aromatic aldehydes on reaction with 2-mercaptoethanol provided an unanticipated product, bis(2-hydroxyethyl)dithioacetals (3) as the major product along with the expected product 1,3-oxathiolanes (4) in the presence of 0.05 equiv amount of nickel(II) chloride hexahydrate (NiCl2-6H(2)O) under solvent-free conditions. Products 3c and 3e exhibit an interesting hydrogen-bonded infinite supra-molecular helical structure. (C) 2013 Elsevier Ltd. All rights reserved.