TY  - JOUR
A1  - Karras, Manfred
A1  - Dabrowski, Michal
A1  - Pohl, Radek
A1  - Rybacek, Jiri
A1  - Vacek, Jaroslav
A1  - Bednarova, Lucie
A1  - Grela, Karol
A1  - Stary, Ivo
A1  - Stara, Irena G.
A1  - Schmidt, Bernd
T1  - Helicenes as Chirality-Inducing Groups in Transition-Metal Catalysis
BT  - the first helically chiral Olefin Metathesis Catalyst
JF  - Chemistry - a European journal
N2  - Helical chirality is a novel enantioselectivity-inducing property in transition-metal-catalyzed transformations. The principle is illustrated herein for the example of asymmetric olefin metathesis. This work reports the synthesis of the first helically chiral Ru-NHC alkylidene complex from an aminohelicene-derived imidazolium salt, which was ligated to the first generation Hoveyda-Grubbs catalyst. Kinetic data were acquired for benchmark test reactions and compared to an achiral catalyst. The helically chiral Ru-catalyst was evaluated in asymmetric ring-closing metathesis (RCM) and ring-opening metathesis-cross-metathesis (ROM/CM) reactions, which proceeded with promising levels of enantioselectivity. Extensive NMR-spectroscopic investigations and a DFT geometry optimization were performed. These results led to a topographic steric map and calculation of percent-buried-volume values for each quadrant around the metal center.
KW  - asymmetric catalysis
KW  - carbene ligands
KW  - helicenes
KW  - metathesis
KW  - ruthenium
Y1  - 2018
U6  - https://doi.org/10.1002/chem.201802786
SN  - 0947-6539
SN  - 1521-3765
VL  - 24
IS  - 43
SP  - 10994
EP  - 10998
PB  - Wiley-VCH
CY  - Weinheim
ER  -