已经证明了从 α、β-炔基酮和酯合成 β-羰基取代的叔醇的新策略。硅系链用于内部传递烷基,该烷基与 C-Si 到 CO 的转化相结合,可以在吸电子基团的 β 位以区域和非对映选择性“缝合”成对的 CC 和 CO 键。通过反式加成工艺的区域选择性炔烃氢化硅烷化提供了获得三取代乙烯基硅烷的清洁途径。随后的一锅氟化物诱导的 CC 键形成和所得叔硅烷(一种通常对此类条件不具有反应性的硅烷)的氧化提供所需的产物。相邻的酮和羧酸酯基团在促进这些高度受阻叔醇的氧化中的效用,证明了可能会影响取决于此类氧化的路线合成设计的观察结果。对于带有 γ-烷氧基立体中心的底物,观察到良好的非对映选择 (>10:1)。
Silicon-Directed Rhenium-Catalyzed Allylic Carbaminations and Oxidative Fragmentations of γ-Silyl Allylic Alcohols
作者:Sanjay W. Chavhan、Matthew J. Cook
DOI:10.1002/chem.201400104
日期:2014.4.22
A highly regioselective allylic substitution of β‐silyl allylic alcohols has been achieved that provides the branched isomer as a single product. This high level of regiocontrol is achieved through the use of a vinyl silane group that can perform a Hiyama coupling providing 1,3‐disubstituted allylic amines. An unusual oxidative fragmentation product was also observed at elevated temperature that appears
Activation of silanes by Grubbs’ carbene complex Cl2(PCy3)2RuCHPh: dehydrogenative condensation of alcohols and hydrosilylation of carbonyls
作者:Sarah V Maifeld、Reagan L Miller、Daesung Lee
DOI:10.1016/s0040-4039(02)01385-0
日期:2002.9
This manuscript describes two catalytic methods for silylether synthesis using Grubbs’ catalyst Cl2(PCy3)2RuCHPh. Silylethers are obtained from the reaction of a variety of silanes with alcohols by dehydrogenative condensation and by the hydrosilylation of carbonyl compounds. Both reactions occur under neat conditions.
An analysis of the influences dictating regioselectivity in platinum-catalyzed hydrosilylations of internal alkynes
作者:Douglas A. Rooke、Zachary A. Menard、Eric M. Ferreira
DOI:10.1016/j.tet.2014.03.012
日期:2014.7
A full account of our studies on internal alkyne hydrosilylations using platinum catalysis is described. We demonstrate that these transformations are highly governed by the electronic characteristics of the alkyne substituents, wherein the hydride will add preferentially to the more electron-deficient alkyne carbon. The steric and coordinative capabilities of the substituents influence the selectivity
完整介绍了我们对使用铂催化的内部炔烃氢甲硅烷基化的研究。我们证明,这些转变高度受炔烃取代基的电子特性支配,其中氢化物将优先添加至电子欠缺的炔烃碳上。取代基的空间和配位能力对选择性的影响程度要小得多,其中丙炔醇是唯一的例外。硅烷的选择在某些情况下是相关的。特定的硅烷将提供较高的区域选择性,而其他的则选择性要低得多。最终,使用13 C NMR化学位移数据可以完全预测加成的区域选择性,从而将这种反应性纳入目标反应设计中。
Alkyne Hydrosilylation Catalyzed by a Cationic Ruthenium Complex: Efficient and General Trans Addition
作者:Barry M. Trost、Zachary T. Ball
DOI:10.1021/ja0528580
日期:2005.12.1
The complex [Cp*Ru(MeCN)3]PF6 is shown to catalyze the hydrosilylation of a wide range of alkynes. Terminalalkynes afford access to alpha-vinylsilane products with good regioselectivity. Deuterium labeling studies indicate a clean trans addition process is at work. The same complex is active in internal alkyne hydrosilylation, where absolute selectivity for the trans addition process is maintained
Morphology-Controlled Synthesis of Poly(oxyethylene)silicone or Alkylsilicone Surfactants with Explicit, Atomically Defined, Branched, Hydrophobic Tails
作者:Ferdinand Gonzaga、John B. Grande、Michael A. Brook
DOI:10.1002/chem.201103093
日期:2012.1.27
Siliconesurfactants are widely used in commerce because of the unusual surface activity when compared with fluorocarbon or hydrocarbon surfactants. However, most siliconesurfactants are comprised of ill‐defined mixtures, which preclude the development of an understanding of structure–surface activity relationships. Herein, we report a synthetic strategy that permits exquisite control over silicone
有机硅表面活性剂与氟碳或烃类表面活性剂相比具有异常的表面活性,因此在商业上得到了广泛的应用。但是,大多数有机硅表面活性剂由不明确的混合物组成,这妨碍了人们对结构与表面活性关系的理解。在这里,我们报告了一种合成策略,该策略允许通过使用B(C 6 F 5)3来精确控制硅酮结构氢和烷氧基硅烷的催化缩合。然后,通过无金属的点击环化反应,将六种不同的精确疏水物与三种分子量的亲水性聚氧乙烯交联,生成一个显性有机硅表面活性剂库。这些化合物经计算具有亲水性-亲脂性平衡的相对线性值范围,约8到约15。某些化合物的溶解度太低,无法测量临界胶束浓度(CMC)。其他的在CMC上表现出宽范围的表面张力值,这取决于亲水性尾基的长度,更重要的是,取决于疏水性头基的性质。表面活性剂相关特性的细微差别可以归因于三维结构,