To a stirred solution of 99.6 g (0.46 mol) of 2,6-diethyl-1-hydroxy-2,3,6-trimethyl-piperidin-4-one (prepared as described in U.S. Pat. No. 6,353,107 B1, example 2), 66.3 g (0.46 mol) of CuBr and 29.4 g (0.46 mol) Cupper in 1000 ml toluene 160 g (0.92 mol) of N,N,N′,N″,N″-pentamethyldiethylenetriamine (PMDTA) are added. The brown suspension is then cooled to 10° C. and 116 g (0.46 mol) of acrylic acid 2-(2-bromo-propionyloxy)-ethyl ester dissolved in 250 ml toluene are added dropwise while keeping the temperature below 15° C. The reaction mixture is stirred for another 12 h at room temperature and then filtered. The filtrate is washed with water (3×500 ml), then with a 10% solution of EDTA (3×500 ml), dried over NaSO4 and evaporated. The residue is chromatographed over Silica gel with hexane-ether (7:3) to afford 165 g of the title compound as slightly yellow oil.
