Supramolecular Assemblies as Promoters of Iodohydrin Formation

Finding alternative reaction media to replace polluting organic solvents is one aim of green chemistry. The ultimate green solvent, water, is the cheapest, non-toxic and most readily available reaction medium: three properties which make it an environmentally and economically attractive solvent. However, a fundamental problem in performing reactions in water is that many organic substrates are hydrophobic and not soluble in water. Several approaches are possible in solubilizing these compounds in aqueous media, one of which is carrying out reactions in aqueous solutions of surfactants at concentrations above their critical micellar concentration (cmc). Reactions of iodine with cyclohexene, 1-octene and styrene in water or in the presence of cationic sur- Introduction Alkenes react readily across the double bond.[1] Electrophilic additions to unsaturated compounds, where the electrophile is a halogen molecule or derivative and the nucleophile is the alkene, are shown in the following scheme (Figure 1). Figure 1. Scheme of halogenation of alkenes by iodine in water The main importance of these processes is that they generate saturated compounds with the potential to have different vicinal substituents in a single-step reaction. For example, newly formed α-halohydrins are attractive as they can be used in further reactions because they are useful intermediates and are targets in organic syntheses. [a] Institute for Biomedical Engineering, Swiss Institute of Technology and University Zurich, Moussonstr. 18, 8044 Zürich, Switzerland [b] Dipartimento di Chimica, Ingegneria Chimica e Materiali, Universita` dell’Aquila, Via Vetoio, 67010 Coppito LAquila, Italy Fax: (internat.) 39-0862-433753 E-mail: cerichel@univaq.it Eur. J. Org. Chem. 2004, 623630 DOI: 10.1002/ejoc.200300085  2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim 623 factants do not give useful amounts of iodohydrins, but reactions in anionic surfactants give good yields. Iodohydrins are important functionalizable compounds and are readily prepared in the presence of sodium dodecyl sulfate (SDS) or sodium N-dodecanoyl sarcosinate (SANa). The critical conditions for these reactions were optimized with a rigorous statistical approach, the experimental design method. Use of these newly optimized reaction conditions gave high yields in short times for all of the alkenes examined. The use of anionic surfactants in water to form iodohydrins is a valid alternative to methods previously described.