Catalytic osmylation of conjugated dienes: a one-pot stereoselective synthesis of polyols
作者:Christine Y. Park、B.Moon Kim、K.Barry Sharpless
DOI:10.1016/s0040-4039(00)74472-8
日期:1991.2
Conjugateddienes have been hydroxylated with catalytic amounts of osmium tetroxide. The reaction can be highly stereoselective depending on the nature of the terminal substituents, leading to polyols of predictable configurations.
作者:Laura L. Adduci、Matthew P. McLaughlin、Trandon A. Bender、Jennifer J. Becker、Michel R. Gagné
DOI:10.1002/anie.201306864
日期:2014.2.3
catalyze the metal‐free hydrosilylative reduction of monosaccharides and polysaccharides to give hydrocarbons with reduced oxygen content. The choice of the silane reductant influences the degree of deoxygenation, with diethylsilane effecting the complete reduction to produce hexanes while tertiary silanes give partially deoxygenated tetraol and triol products.
易于获得的纤维素生物质向有价值的原料和燃料的转化是一个吸引人的目标,但具有挑战性的转化需要裂解多个未活化的CO键。在此,路易斯酸三五氟苯基硼烷(B(C 6 F 5)3)被证明可催化单糖和多糖的无金属氢化硅烷化还原,从而制得氧含量降低的烃。硅烷还原剂的选择会影响脱氧程度,二乙基硅烷会完全还原生成己烷,而叔硅烷会产生部分脱氧的四醇和三醇产物。
Chemoselective conversion of biologically sourced polyols into chiral synthons
作者:Laura L. Adduci、Trandon A. Bender、Jennifer A. Dabrowski、Michel R. Gagné
DOI:10.1038/nchem.2277
日期:2015.7
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
原油目前提供世界上大部分能源,但它也是许多原料化学品的来源。用于将生物质转化为有用化学物质的方法学通常集中在完全脱氧或大批量平台化学物质的生产上。在这里,我们描述了甲硅烷基保护的C 6 O 6衍生的多元醇的化学选择性部分还原,以产生各种不同的氧官能化手性合成子。B(C的组合6 ˚F 5)3和叔硅烷有效地产生亲电甲硅烷鎓离子(R的反应性等价物3的Si +)和氢化物(H -) 还原剂。氧损失的机理不涉及脱水消除,因此避免了立体化学的消融。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,并且在同时存在伯和仲C-O键的情况下,该机理可以进一步控制。该方法在一个或两个合成步骤中提供了许多C 6 O n合成子以及几种先前未描述的产物的高度改进的合成方法。
Modulating Electrostatic Interactions in Ion Pair Intermediates To Alter Site Selectivity in the C−O Deoxygenation of Sugars
作者:Jared M. Lowe、Bekah E. Bowers、Youngran Seo、Michel R. Gagné
DOI:10.1002/anie.202007415
日期:2020.9.21
oligosaccharides. Computational methods helped identify this non‐intuitive outcome in low dielectric solvents to non‐isotropic electrostatic enhancements in the key ion pair intermediates, which influence the reaction coordinate in the reactivity‐/selectivity‐determining step. Molecular‐level models for these effects have far‐reaching consequences in stereoselective ion pair catalysis.