ozone; triphenylphosphine in dichloromethane T=-78 - 20°C;

1: CoBr2(1,2-bis(diphenylphosphino)ethane); zinc(II) iodide; zinc / dichloromethane / 20 °C / Inert atmosphere 2: hydrogenchloride; water / diethyl ether 3: ozone; triphenylphosphine / dichloromethane / -78 - 20 °C View Scheme

5-(2-hydroxyethyl)-4-methyl-3-(phenylmethyl)thiazolium chloride; triethylamine in N,N-dimethyl-formamide