Regioselective Formation of Enol Esters from the Ruthenium-Catalyzed Markovnikov Addition of Carboxylic Acids to Alkynes
作者:Janine Jeschke、Christian Gäbler、Heinrich Lang
DOI:10.1021/acs.joc.5b02293
日期:2016.1.15
selectivities with up to 99% of the Markovnikov product were achieved. The electronic influence of the substrates on the reaction rate was quantified by Hammett plots. By the use of electron-rich alkynes or highly acidic carboxylic acids, the reaction rate could be increased. Hence, the addition of highly acidic pentafluorobenzoic acid to electron-rich 4-methoxyphenylacetylene can even be carried out
Rh(I)/DpenPhos catalyzed asymmetric hydrogenation of enol esters and potassium (E)-3-cyano-5-methylhex-3-enoate
作者:Yan Liu、Zheng Wang、Kuiling Ding
DOI:10.1016/j.tet.2012.05.096
日期:2012.9
class of modular chiral monodentate phosphoramidites were highly efficient for the asymmetric hydrogenation of enolesters bearing α-aryl or α-alkyl groups, to afford the corresponding hydrogenation products in high enantioselectivities (87–95% ee) and reactivities (turnover number up to 10,000). These ligands were also shown to be effective in Rh(I)-catalyzed asymmetric hydrogenation of the potassium
Catalytic Asymmetric Hydrogen Atom Transfer: Enantioselective Hydroamination of Alkenes
作者:Benjamin G. Hejna、Jacob M. Ganley、Huiling Shao、Haowen Tian、Jonathan D. Ellefsen、Nicholas J. Fastuca、Kendall N. Houk、Scott J. Miller、Robert R. Knowles
DOI:10.1021/jacs.3c04591
日期:2023.7.26
report a highly enantioselective radical-based hydroamination of enol esters with sulfonamides jointly catalyzed by an Ir photocatalyst, Brønsted base, and tetrapeptide thiol. This method is demonstrated for the formation of 23 protected β-amino-alcohol products, achieving selectivities up to 97:3 er. The stereochemistry of the product is set through selective hydrogen atom transfer from the chiral
我们报道了在 Ir 光催化剂、布朗斯台德碱和四肽硫醇的共同催化下,烯醇酯与磺酰胺发生高度对映选择性自由基加氢胺化。该方法已被证明可形成 23 种受保护的 β-氨基醇产物,选择性高达 97:3 er。产物的立体化学是通过选择性氢原子从手性硫醇催化剂转移到前手性C中心自由基来设定的。由肽催化剂和烯烃底物的结构变化衍生的结构-选择性关系为开发最佳催化剂提供了关键见解。实验和计算机制研究表明,氢键、π-π堆积和伦敦色散相互作用是底物识别和对映诱导的影响因素。这些发现进一步促进了基于自由基的不对称催化的发展,并有助于理解与此类转化相关的非共价相互作用。