Treatment of 3-aminocyclohex-1-enes with mCPBA in the presence of trichloroacetic acid gives the corresponding 1,2-anti-2,3-syn-1-trichloroacetoxy-2-hydroxy-3-aminocyclohexane with high levels of diastereoselectivity (90% de). This is consistent with a mechanism of oxidation involving hydrogen-bonded delivery of the oxidant by the allylic ammonium ion formed in situ, followed by highly regioselective ring-opening of the intermediate epoxide by trichloroacetic acid. The effect of conformational constraints upon the oxidation reaction is also examined.
在有
三氯乙酸存在的情况下,用 mCPBA 处理 3-aminocyclohex-1-enes 可得到相应的 1,2-反-2,3-辛-1-三
氯乙酰氧基-2-羟基-3-aminocyclohexane,具有很高的非对映选择性(90% de)。这与原位形成的烯丙基
铵离子以氢键传递氧化剂,然后
三氯乙酸对中间
环氧化物进行高区域选择性开环的氧化机理是一致的。此外,还研究了构象限制对氧化反应的影响。