Asymmetric Synthesis of Diastereo- and Enantiopure Bioxahelicene 2,2′-Bipyridines
作者:Jiří Klívar、Michal Šámal、Andrej Jančařík、Jaroslav Vacek、Lucie Bednárová、Miloš Buděšínský、Pavel Fiedler、Ivo Starý、Irena G. Stará
DOI:10.1002/ejoc.201800541
日期:2018.10.9
Enantio‐ and diastereopure bioxahelicene 2,2′‐bipyridines were synthesized employing dicyanotetrayne cycloisomerization or triyne cycloisomerization–haloazaoxahelicene homocoupling. An effective central‐to‐helical‐to‐axial chirality transfer was reached.
Synthesis of Racemic, Diastereopure, and Enantiopure Carba- or Oxa[5]-, [6]-, [7]-, and -[19]helicene (Di)thiol Derivatives
作者:Jindřich Nejedlý、Michal Šámal、Jiří Rybáček、Isabel Gay Sánchez、Václav Houska、Tomáš Warzecha、Jaroslav Vacek、Ladislav Sieger、Miloš Buděšínský、Lucie Bednárová、Pavel Fiedler、Ivana Císařová、Ivo Starý、Irena G. Stará
DOI:10.1021/acs.joc.9b02965
日期:2020.1.3
A series of carba- or oxa[5]-, [6]-, [7]-, and -[19]helicene (di)thiols was prepared. The Miyazaki-Newman-Kwart rearrangement of (dimethylcarbamothioyl)oxy (oxa)helicenes in a flow reactor or nucleophilic substitution of dichloro (oxa)helicenes with alkanethiolates were used in the sulfanylation step. Despite the high temperatures employed in this key step, no conformational scrambling was observed
Cycloiridated Helicenes as Chiral Catalysts in the Asymmetric Transfer Hydrogenation of Imines
作者:Daisuke Sakamoto、Isabel Gay Sánchez、Jiří Rybáček、Jaroslav Vacek、Lucie Bednárová、Markéta Pazderková、Radek Pohl、Ivana Císařová、Irena G. Stará、Ivo Starý
DOI:10.1021/acscatal.2c01816
日期:2022.9.2
The asymmetric synthesis of optically pure and conformationally locked oxabenzo[5]helicenes bearing pyridin-2-yl or isoquinolin-3-yl substituents and their transformation into the corresponding cycloiridated organometallics are described. These helically chiral Cp*IrIII(X)C,N-complexes (X = Cl, I) also contain a configurationally unstable pseudotetrahedral iridium center. This center undergoes epimerization
描述了带有 pyridin-2-yl 或 isoquinolin-3-yl 取代基的光学纯和构象锁定的氧杂苯并 [5] 螺旋烯的不对称合成及其转化为相应的环化有机金属。这些螺旋手性 Cp*Ir III (X)C,N-配合物 (X = Cl, I) 还包含一个构型不稳定的假四面体铱中心。该中心在室温下进行差向异构化,其相对立体化学,尤其是在固态下,取决于配位配体的性质。环化螺旋烯用于前手性芳族亚胺与甲酸/三乙胺的不对称转移氢化,达到 96:4 er。假设手性转移是由辅助螺旋而不是 Ir III控制的手性铱环的立体中心。