An efficient synthesis of natural tribolure has been achieved through an asymmetric methylation as a key step. Natural tribolure is a mixture of four stereoisomers, so racemic 2-methylbutan-1-ol was used as starting material. After a C5+C4 strategy and then a mixed Evan’s template inductive methylation, the key intermediate was obtained. Finally, the natural product tribolure (4:4:1:1 of stereoisomers, respectively) was obtained in 10 linear steps and in 34.2% overall yield.

中文翻译：

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天然摩擦的有效合成

通过作为关键步骤的不对称甲基化实现了天然摩擦的有效合成。天然摩擦剂是四种立体异构体的混合物，因此使用外消旋 2-methylbutan-1-ol 作为起始原料。经过C5+C4策略和混合Evan's模板诱导甲基化后，得到了关键中间体。最后，在 10 个线性步骤中以 34.2% 的总产率获得了天然产物 tribolure（立体异构体分别为 4:4:1:1）。