Application of Tethered Ruthenium Catalysts to Asymmetric Hydrogenation of Ketones, and the Selective Hydrogenation of Aldehydes
作者:Katherine E. Jolley、Antonio Zanotti‐Gerosa、Fred Hancock、Alan Dyke、Damian M. Grainger、Jonathan A. Medlock、Hans G. Nedden、Jacques J. M. Le Paih、Stephen J. Roseblade、Andreas Seger、Vilvanathan Sivakumar、Ivan Prokes、David J. Morris、Martin Wills
DOI:10.1002/adsc.201200362
日期:2012.9.17
An improved method for the synthesis of tethered ruthenium(II) complexes of monosulfonylated diamines is described, together with their application to the hydrogenation of ketones and aldehydes. The complexes were applied directly, in their chloride form, to asymmetric ketone hydrogenation, to give products in excess of 99% ee in the best cases, using 30 bar of hydrogen at 60 °C, and to the selective
<i>ansa</i>-Ruthenium(II) Complexes of R<sub>2</sub>NSO<sub>2</sub>DPEN-(CH<sub>2</sub>)<sub>n</sub>(η<sup>6</sup>-Aryl) Conjugate Ligands for Asymmetric Transfer Hydrogenation of Aryl Ketones
作者:Andrea Kišić、Michel Stephan、Barbara Mohar
DOI:10.1002/adsc.201500288
日期:2015.8.10
New 3rd generation designer ansa‐ruthenium(II) complexes featuring N,C‐alkylene‐tethered N,N‐dialkylsulfamoyl‐DPEN/η6‐arene ligands, exhibited good catalytic performance in the asymmetric transfer hydrogenation (ATH) of various classes of (het)aryl ketones in formic acid/triethylamine mixture. In particular, benzo‐fused cyclic ketones furnished 98 to >99.9% ee using a low catalyst loading.
Organocatalyzed Birch Reduction Driven by Visible Light
作者:Justin P. Cole、Dian-Feng Chen、Max Kudisch、Ryan M. Pearson、Chern-Hooi Lim、Garret M. Miyake
DOI:10.1021/jacs.0c05899
日期:2020.8.5
The Birchreduction is a powerful synthetic methodology that uses solvated electrons to convert inert arenes to 1,4-cyclohexadienes-valuable intermediates for building molecular complexity. Birchreductions traditionally employ alkali metals dissolved in ammonia to produce a solvated electrons for the reduction of unactivated arenes such as benzene (Ered < -3.42 V vs. SCE). Photoredox catalysts have
Birch 还原是一种强大的合成方法,它使用溶剂化电子将惰性芳烃转化为 1,4-环己二烯有价值的中间体,以构建分子复杂性。桦木还原传统上使用溶解在氨中的碱金属来产生溶剂化电子,用于还原未活化的芳烃,例如苯(Ered < -3.42 V vs. SCE)。光氧化还原催化剂在高度还原应用中越来越受欢迎,但没有报道显示出足以减少苯的还原潜力。在这里,我们引入苯并苝酰亚胺作为新型有机光氧化还原催化剂,用于在环境温度下进行桦木还原,并由市售 LED 的可见光驱动。使用低催化剂负载量(<1 摩尔百分比),在完全无金属的反应中,苯和其他官能化芳烃以中等至良好的产率选择性地转化为 1,4-环己二烯。机理研究表明,这种前所未有的可见光诱导反应是通过有机光氧化还原催化剂利用两个可见光光子的能量影响单个高能化学转化的能力实现的。
<i>trans</i>-Diastereoselective Ru(II)-Catalyzed Asymmetric Transfer Hydrogenation of α-Acetamido Benzocyclic Ketones via Dynamic Kinetic Resolution
A highly efficient enantio- and diastereoselective catalyzed asymmetrictransferhydrogenation via dynamic kinetic resolution (DKR–ATH) of α,β-dehydro-α-acetamido and α-acetamido benzocyclic ketones to ent-trans-β-amido alcohols is disclosed employing a new ansa-Ru(II) complex of an enantiomericallypure syn-N,N-ligand, i.e. ent-syn-ULTAM-(CH2)3Ph. DFT calculations of the transition state structures
A Practical Synthesis of the Kappa Opioid Receptor Selective Agonist (+)-5<b><i>R</i></b>,7<b><i>S</i></b>,8<b><i>S</i></b>-<b><i>N</i></b>-Methyl-<b><i>N</i></b>-[7-(1-pyrrolidinyl)-1-oxospiro[4,5]dec-8-yl]benzeneacetamide (U69,593)
A novel approach to the synthesis of the kappa opioid receptor agonist U69,593 has been developed. This approach improves upon current literature methods by substituting stable and isolable cyclic sulfates for the unstable epoxides. The new approach provides access to gram quantities of the target compound and displays excellent control of the relative stereochemistry. The absolute stereochemistry as well as biological activity of the U69,593 produced by this new method was verified using X-ray crystal structure analysis and binding assays for the kappa opioid receptor.