1: 2,3,4,6-tetra-O-acetyl-D-glucono-1,5-lactone With sodium borodeuteride; water-d2 in tetrahydrofuran T=0°C; 2: acetic anhydride in tetrahydrofuran T=20°C; 0.5 h; Further stages.;

sodium borodeuteride in tetrahydrofuran; water-d2 1.) 0 deg C, 1 h, 2.) RT; overnight,;

toluene-4-sulfonic acid T=20°C; 1 h;