DOI: 10.1002/chem.201101985 Ring-Closing Metathesis in Aqueous Micellar Medium Lionel Laville, [a, b] Clarence Charnay,* [b] FrØdØric Lamaty, [a] Jean Martinez, [a] and Evelina Colacino* [a] One approach towards the development of environmen- tal-friendly synthetic processes is the use of ecologic, healthy, and safe alternative reaction media to replace the classical volatile organic solvents. [1] Although water has no environmental impact, its use has been limited in organic transformations [2] because of the low solubility of substrates. In this perspective, and for a chemistry that is “benign by design”, [3] we turned our attention towards one of the most powerful reactions for the formation of carbon–carbon double bonds: olefin metathesis. [4] Several examples of olefin metathesis with water as solvent have been report- ed, [5] and different ways to solve the problem of low catalyst solubility have been proposed, for example by adding an or- ganic cosolvent, [6] by synthesizing water-soluble catalysts, [7] or by using the so called “catsurf”-modified catalysts. [8] An alternative and still underdeveloped way to overcome the problem of heterogeneity of organic reactions in aqueous medium is micellar catalysis, [9] which achieve cross metathe- sis (CM) and ring-closing metathesis (RCM). [8c, 10] Unfortu- nately, the adsorption mechanism that leads to product for- mation under micellar conditions has not been investigated for any of these procedures. For this reason, we decided to study this mechanism by means of 1 H NMR and zeta-poten- tial investigations and new data are reported on the interac- tions between micelles and commonly used olefins for RCM, which leads to five-membered cycles. We focused our attention on the RCM of N,N-diallyltosylamine (4, DATs) in micellar conditions (Scheme 1), catalyzed by the 1st gen- eration Grubbs (1a) and Hoveyda–Grubbs (2a), Zhan-1C [11] (3a) and Zhan-1B [11] (3b) precatalysts (Scheme 2), in the presence of four previously described gemini (dimeric) cat- ionic surfactants (Scheme 3). [12] These surfactants, formed by two amphiphilic units linked with a molecular spacer, were selected because they exhibit- ed enhanced surface activities compared with those of the corresponding monocationic compounds. In the present study, two types of amphiphiles were investigated, those with a polymethylene spacer, referred to as 12-s-12 for which s represents the number of methylene groups (2 or 10), and those with a polyoxyethylene spacer (i.e., PEG- based surfactants), referred to as 12-EO x -12 for which x is the number of ethylene oxide groups (1 or 6, Scheme 3). Independent of the combination surfactant/precatalyst, full conversion of substrate 4 was always achieved after four hours of stirring at room temperature. High yields of prod- uct 5 [13] were always obtained. The results are summarized in Table 1. When the experiment was run in the absence of surfactant (Table 1) complete conversion of starting material 4 was possible only after 24 h at room temperature; this shows the beneficial influence of the gemini surfactants. To go deeper in the elucidation of the adsorption mechanism involved in [a] L. Laville, Dr. F. Lamaty, Prof. J. Martinez, Dr.E. Colacino Institut des BiomolØcules Max Mousseron (IBMM) UMR 5247 CNRS—UM I-UM II UniversitØ Montpellier II, Place E. Bataillon 34095 Montpellier Cedex 5 (France) Fax: (+ 33) 4-67-14-48-66 E-mail : evelina.colacino@univ-montp2.fr [b] L. Laville, Dr. C. Charnay Institut Charles Gerhardt Montpellier (ICGM), Equipe AgrØgats Interfaces et MatØriaux pour l’Energie, CNRS UMR 5253 UniversitØ Montpellier II, Place E. Bataillon 34095 Montpellier Cedex 5 (France) Fax: (+ 33) 4-67-14-33-04 E-mail : clarence.charnay@univ-montp2.fr Supporting information for this article is available on the WWW under http://dx.doi.org/10.1002/chem.201101985. Scheme 1. Scheme of the RCM reaction of 4. Scheme 2. Chemical structure of the RCM commercial catalysts used.  2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim Chem. Eur. J. 2012, 18, 760 – 764 760