FULL PAPER DOI: 10.1002/ejoc.200600711 A New Target for Highly Stereoselective Katsuki–Sharpless Epoxidation – One-Pot Synthesis of C 2 -Symmetric 2,2'-Bioxiranes Vitaliy Bilenko, [a,b] Haijun Jiao, [a] Anke Spannenberg, [a] Christine Fischer, [a] Helmut Reinke, [c] Jutta Kösters, [d] Igor Komarov, [b] and Armin Börner* [a,c] Keywords: Epoxidation / Asymmetric catalysis / Bis-epoxides / Diols / ab initio calculation The double asymmetric Katsuki–Sharpless epoxidation of a conjugated diallyl alcohol affords excellent enantioselectivity (97 % ee), the product being isolated as the stable p-nitro- benzoate 5a or tosylate 5b. The optical purities of the chiral epoxides were determined by HPLC on chiral columns, while the molecular structures of compounds 5a and 7 and the ab- Introduction The asymmetric Katsuki–Sharpless epoxidation of allyl alcohols plays a pivotal role in organic chemistry for the generation of chiral epoxides, [1,2] which serve as useful chi- ral building blocks for further transformations. The cata- lytic reaction does not require expensive reagents or special equipment, while the mild reaction conditions and the tol- eration of a range of functional groups are especially note- worthy. In general, the stereochemistry of the resultant ep- oxy alcohols can be unambiguously predicted by common rules. In the case of Lewis acid-sensitive epoxides a facile in situ derivatization has been suggested. [3] In a few cases, stereoselective bis-epoxidation of prochi- ral diallyl alcohols has also been investigated. [4] The double epoxidation also usually proceeds with high diastereo- and enantioselectivity, but it is interesting to note that conju- gated dienes have never been subjected to Katsuki– Sharpless epoxidation. Here we report the first example of this transformation, which proceeds with high stereoselecti- vity. The products of such transformations might serve as building blocks in syntheses of chiral multifunctional com- pounds, in particular as chiral ligands for enantioselective catalysts. [a] Leibniz-Institut für Katalyse e.V., A.-Einstein-Str. 29a, 18059 Rostock, Germany Fax: +49-381-1281-5202 E-mail: armin.boerner@catalysis.de [b] Kyiv Taras Shevchenko University, Volodymyrska-Str. 64, 01033 Kyiv, Ukraine [c] Institut für Chemie der Universität Rostock, A.-Einstein-Str. 3a, 18059 Rostock, Germany [d] Institut für Anorganische und Analytische Chemie, Universität Münster, Corrensstrasse 36, 48149 Münster, Germany © 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim Eur. J. Org. Chem. 2007, 758–767 758 solute configuration of mono-epoxide 12 were confirmed by X-ray crystallography. Possible π–π stacking interaction has been evaluated by ab initio calculation. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) Results and Discussion 1. Synthesis of Diallyl Alcohol As a substrate for the epoxidation we chose the hydroxy- functionalized (E,E)-butadiene 4, which is easily available by the synthetic route depicted in Scheme 1. Scheme 1. Synthesis of diallyl alcohol 4 used as substrate in the Katsuki–Sharpless epoxidation.