Qs As 10s04 OH 2 NaHSO3,H2O OH KMnO4 cold,diluted OH OH Stereoselectivity Syn-addition College Qs ＆ As of Science KMnO4 1 OsO4 2 NaHSO3，H2O cold,diluted OH OH OH OH Stereoselectivity Syn-addition