12 ml of trimethylaluminum of a 10% solution in hexane (12 mmol) is introduced at room temperature under nitrogen atmosphere. With stirring, 2.64 g of 2,6-di-tert-butyl-4-methylphenol is added in portions. The solution is stirred for 30 more minutes and 3.27 g (10 mmol) of 17β-acetoxy-androsta-l,4-dien-3-one in 20 ml of ethyl acetate is added at 25° C. The solution is heated to 60° C. and 143 mg of nickel(II)-acetylacetonate is added at 60° C. The solution is stirred for another 2.5 hours at this temperature. After cooling, 1.1 ml water is added for hydrolysis and stirred for 15 minutes. The solid is filtered off, rewashed twice-with 50 ml of ethyl, acetate. After concentration by evaporation of the ethyl acetate phases, a crude product is obtained, which is chromatographed on silica gel with hexane/ethyl acetate as eluent with increasing ethyl acetate portion. 1.55 g of initial material is recovered. 0.68 g of 17β-acetoxy-l-methyl-androsta-1,4-dien-3-one of melting point 144.1° C. is obtained. The yield is 20% of theory or 38% taking into consideration the initial material recovered.
