Herein, we report for the first time a “trans-hydroboration–oxidation product” isolated and characterized under traditional hydroboration–oxidation conditions using cholesterol and diosgenin as substrates. These substrates are excellent starting materials because of the rigidity and different structural environments around the double bond. Further investigations based on experimental evidence, in conjunction with theoretical studies, indicate that the formation of this trans-species occurs via a retro-hydroboration of the major product to generate the corresponding Δ⁶-structure and the subsequent hydroboration by the β-face. Besides, the corresponding Markovnikov type products have been isolated in synthetically useful yields. The behavior of the reaction under a range of temperatures is also investigated.

中文翻译：

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通过硼氢化-还原-硼氢化作用机理在Δ5-类固醇中进行反硼氢化-氧化产物

在此，我们首次报道了以胆固醇和薯os皂甙元为底物，在传统的硼氢化-氧化条件下分离和表征的“反式-硼氢化-氧化产物”。这些基材是优良的原材料，因为其刚性和双键周围的结构环境不同。基于实验证据进一步调查，与理论研究相结合，表明这形成反式-species发生经由一个复古主要产物的-hydroboration产生相应的Δ ⁶-结构和随后的β面硼氢化。此外，已经以合成有用的产率分离了相应的马尔可夫尼科夫型产物。还研究了在一定温度范围内反应的行为。