390 H CH CH2C-Ch +HO HO C-OH -H CH CH3 CH H OH ●Ho《C-OH HO C+ HO CH CH CH CH OH/O OH H+ HO OH CH CH ⑨DOrganic Chemistry Organic Chemistry Xiamen Xiamen University University CH 3 C C H 3 O H + HO HO C CH 3 CH 3 OH H HO C CH 3 CH 3 OH H + H 2 O HO C CH 3 CH 3 OH HO C CH 3 CH 3 OH − H + H − H + HO C CH 3 CH 3 OH