Chemoselective conversion of biologically sourced polyols into chiral synthons
Chemoselective conversion of biologically sourced polyols into chiral synthons
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DOI：
10.1038/nchem.2277
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发表时间：
2015-07-01
期刊：
影响因子：
21.8
通讯作者：
Gagne, Michel R.
中科院分区：
文献类型：
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作者：
Adduci, Laura L.;Bender, Trandon A.;Gagne, Michel R.
原油目前提供了世界上大部分的能源，但它也是许多原料化学品的来源。将生物质转化为有用的化学品的方法通常集中在完全脱氧或生产大量平台化学品。在这里，我们描述了甲硅烷基保护的C6 O 6衍生的多元醇的化学选择性部分还原，以产生一组不同的氧官能化的手性双氢离子。B（C6 F5）（3）和叔硅烷的组合有效地产生亲电甲硅烷基鎓离子（R3 Si+）和氢化物（H-）还原剂的反应当量。氧损失的机制不涉及脱水消除，因此避免了立体化学的消除。相邻基团的参与和环状中间体的形成是在这些反应中实现选择性的关键，并且在存在伯和仲C-O键的情况下，该机制允许进一步控制。该方法在一个或两个合成步骤中提供了许多C6 On配体以及几种先前未描述的产物的高度改进的合成。
Crude oil currently provides much of the world's energy, but it is also the source of many feedstock chemicals. Methodology for the conversion of biomass into useful chemicals has often focused on either complete deoxygenation or the production of high-volume platform chemicals. Here, we describe the chemoselective partial reduction of silyl-protected C6O6-derived polyols to produce a diverse set of oxygen-functionalized chiral synthons. The combination of B(C6F5)(3) and a tertiary silane efficiently generates a reactive equivalent of an electrophilic silylium ion (R3Si+) and a hydride (H-) reducing agent. The mechanism of oxygen loss does not involve a dehydrative elimination and thus avoids ablation of stereochemistry. Neighbouring group participation and the formation of cyclic intermediates is key to achieving selectivity in these reactions and, where both primary and secondary C-O bonds are present, the mechanism allows further control. The method provides-in one or two synthetic steps-highly improved syntheses of many C6On synthons as well as several previously undescribed products.