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首页> 外文期刊>Chemistry: A European journal >Asymmetric Allylation of Methyl Ketones by Using Chiral Phenyl Carbinols
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Asymmetric Allylation of Methyl Ketones by Using Chiral Phenyl Carbinols

机译：使用手性苯基甲醇的甲基酮的不对称烯丙基化

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摘要

Novel chiral auxiliaries for the stereoselective allylation of aliphatic methyl ketones with allyltrimethylsilane and their use in the synthesis of homoallylic ethers are described. In a multicomponent domino process catalyzed by trifluoromethanesulfonic acid, the allyl moiety and the auxiliary are transferred onto the substrate to yield tertiary homoallylic ethers. The most useful auxiliary for a general application turned out to be the trimethylsilyl ether of phenyl benzyl carbinol with an induced diastereoselectivity of 90:10 using ethyl methyl ketone and 94:6 using isopropyl methyl ketone as substrates. The transferred substituted benzyl moiety has good protecting properties in Subsequent transformations and can easily be removed under reductive conditions to provide the corresponding homoallylic alcohol. The origin of the high selectivity could be elucidated by identifying the relevant transition states using quantum-chemical calculations. An excellent agreement between calculated and experimentally observed selectivities was obtained assuming an oxocarbenium ion as intermediate.
机译：描述了用于脂族甲基酮与烯丙基三甲基硅烷的立体选择性烯丙基化的新型手性助剂及其在合成均烯丙基醚中的用途。在由三氟甲磺酸催化的多组分多米诺方法中，将烯丙基部分和助剂转移到底物上以产生叔均烯丙基醚。对于一般应用，最有用的助剂是苯基苄基甲醇的三甲基甲硅烷基醚，使用乙基甲基酮诱导的非对映选择性为90:10，使用异丙基甲基酮为94：6。转移的取代的苄基部分在随后的转化中具有良好的保护性能，并且可以容易地在还原条件下除去以提供相应的均烯丙基醇。通过使用量子化学计算确定相关的过渡态，可以阐明高选择性的起源。假定氧碳en离子为中间体，可以得出计算的选择性与实验观察到的选择性之间的极佳一致性。

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