Eco-Friendly Selenium Catalyzed Oxidative Cyclizations

The selenium catalyzed oxidation by hydrogen peroxides was achieved for the synthesis of epoxides¹. Our group recently developed the stereoselective synthesis of anti-1,2-diols passing through an epoxide intermediate² and involving a perselenenic acid as actual catalyst of the whole process. Here we report the cyclofunctionalization of beta,gamma- and gamma,delta unsaturated acids, and alcohols. The stereoselectivity has been investigated starting from substrates containing additional chiral center in the α position as well as optically pure catalysts. All the reactions were carried out using 4 equivalents of hydrogen peroxides (30%) and diselenides as precatalysts without any organic solvents. High regio- and stereo-selectivity were obtained for almost all the substrates but unfortunately using optically pure diselenides only moderated enantiomeric excesses were obtained. The reaction conditions present important eco-friendly features (on water conditions, room temperature and pressure), generally affording high yields. - References - 1) Garcìa-Marìn,H; van der Toorn, J. C.; Mayoral, J. A.; Garcìa, J. I. J. Mol. Catal 2011, 83-88 2) Santoro, S; Santi, C.; Sabatini, M.; Testaferri, L; Tiecco, M. Adv. Synth. Catal. 2008, 350, 2881-2884