CN CHO H OH H OH OH OH CHO CHOH CHOH OH HCN D-赤藓糖 CN CHOH CHO HO D-甘油醛 HO OH OH CHOH CHOH D-苏阿糖 rganIc C emIstryH CHO OH CH2 OH HCN H H OH OH CH2 OH CN H H OH CH2 OH CN HO H H OH OH CH2 OH CHO H H OH CH2 OH CHO HO + (A) (B) D - 甘油醛 D - 赤藓 糖 D - 苏 阿糖