A Combined Experimental and Theoretical Study on the Stereodynamics of Monoaza[5]helicenes: Solvent-Induced Increase of the Enantiomerization Barrier in 1-Aza-[5]helicene.
Helicenes and heterohelicenes are attractive compounds with great potential in materials sciences to be used in optoelectronics as ligand backbones in enantioselective catalysis and as chiral sensors. The properties of these materials are related to the stereodynamics of these helical chiral compounds. However, little is known about features controlling stereodynamics in helicenes; in particular, for heterohelicenes the position of the heteroatom could be relevant in this respect. Herein the complete stereodynamic characterization of monoaza[5]helicenes is shown by enantioselective dynamic HPLC and DFT calculations. At variance with previous theoretical calculations, 1-aza[5]helicene shows a surprisingly high enantiomerization barrier, which is triggered by specific solvent interactions.
Università di Bergamo, INSTM R.U. and Dipartimento di Ingegneria e Scienze Applicate Viale Marconi 5, 24044 Dalmine (Bergamo) (Italy). tullio.caronna@unibg.it.
Tullio
T
Caronna
Politecnico di Milano, Department of Chemistry, Materials and Chemical Engineering "G. Natta", Piazza L. da Vinci 32, 20132 Milano (Italy). andrea.mele@polimi.it.
Andrea
A
Mele
Politecnico di Milano, Department of Chemistry, Materials and Chemical Engineering "G. Natta", Piazza L. da Vinci 32, 20132 Milano (Italy).
Antonino
A
Famulari
Politecnico di Milano, Department of Chemistry, Materials and Chemical Engineering "G. Natta", Piazza L. da Vinci 32, 20132 Milano (Italy).
Daniele
D
Mendola
Università di Bergamo, INSTM R.U. and Dipartimento di Ingegneria e Scienze Applicate Viale Marconi 5, 24044 Dalmine (Bergamo) (Italy).
Francesca
F
Fontana
Corden Pharma Switzerland LLC, Eichenweg 1, 4410 Liestal (Switzerland).
Markus
M
Juza
Ruprecht-Karls Universität Heidelberg, Organisch-Chemisches Institut, Im Neuenheimer Feld 270, 69120 Heidelberg (Germany) www.trapp.uni-hd.de.
Matthias
M
Kamuf
Ruprecht-Karls Universität Heidelberg, Organisch-Chemisches Institut, Im Neuenheimer Feld 270, 69120 Heidelberg (Germany) www.trapp.uni-hd.de.
Kerstin
K
Zawatzky
Ruprecht-Karls Universität Heidelberg, Organisch-Chemisches Institut, Im Neuenheimer Feld 270, 69120 Heidelberg (Germany) www.trapp.uni-hd.de. trapp@oci.uni-heidelberg.de.
Oliver
O
Trapp
D008024:Ligands; D008956:Models, Chemical; D008958:Models, Molecular; D011083:Polycyclic Compounds / Q000737:chemistry*; D011789:Quantum Theory; D013237:Stereoisomerism
D008024:Ligands; D011083:Polycyclic Compounds; C031660:helicenes
DFT calculations; chiral separation; dynamic chromatography; helical structures; heterocycles