1: (+/-)-2,2-dimethyl-1,3-dioxolan-4-ylmethanazide With hydrogenchloride in methanol; diethyl ether; water; ethyl acetate T=0 - 20°C; 2: p-toluenesulfonyl chloride With triethylamine in dichloromethane T=20°C; 3 h;

in pyridine; acetonitrile 1.)0 deg C, 3 days 2.)H2O, r.t., 1 h;

hydrogenchloride; trimethylsilylazide; lithium iso-propoxide; ytterbium(III) triflate 1) THF, r.t., 12 h, 2) THF; Yield given. Multistep reaction. Yields of byproduct given;