H2O p-CH3○-C6H4 CHOCOCH3 烷 外消旋体 p-CH30-C6H4-CHOH 6H5 65 ch cooh Br 大 OH Ph-CH-CH3 CH3OH Ph-CH-CH3 27%构型转化 73%外消旋化C6H5 p CH3O C6H4 CHOCOCH3 * p CH3O C6H4 CHOH C6H5 * + CH3COOH H2O- 二噁烷 外消旋体 Br Ph CH CH3 * OH Ph CH CH3 CH3 OH * 27%构型转化 73%外消旋化