1: triethylamine; hydroxylamine hydrochloride; 1-propanephosphonic acid cyclic anhydride / ethyl acetate; N,N-dimethyl-formamide / 1.25 h / 100 °C 2: diisobutylaluminium hydride; sodium tetrahydroborate; isopropyl alcohol / toluene / -78 - 20 °C 3: anhydrous iron chloride / 1,2-dichloro-ethane / 25 °C View Scheme

1: CrO3*H2O4S / acetone / 1.5 h / 0 °C 2: Amberlyst-15 / toluene / 110 °C View Scheme