hydrogenchloride T=30 - 40°C;

Al(3+)-montmorillonite T=100°C; 48 h; Yield given. Yields of byproduct given. Title compound not separated from byproducts;

1: 1,1-bis(4'-hydroxyphenyl)-2-methylpropane With [1-[1-(1-{2-tert-butoxy-1-[1,2-diphenyl-2-(toluene-4-sulfonylamino)-ethylcarbamoyl]-ethylcarbamoyl}-1-methyl-ethylcarbamoyl)-2-(trityl-carbamoyl)-ethylcarbamoyl]-2-(3-methyl-3H-imidazol-4-yl)-ethyl]-carbamic acid tert-butyl ester in tetrahydrofuran; chloroform 0.5 h; Inert atmosphereCooling; 2: acetic anhydride in tetrahydrofuran; chloroform T=-40°C; 18 h; Inert atmosphere; optical yield given as percent ee;