Are bis(pyridine)iodine() complexes applicable for asymmetric halogenation?

Enantiopure halogenated molecules are of tremendous importance as synthetic intermediates in the construction of pharmaceuticals, fragrances, flavours, natural products, pesticides, and functional materials. Enantioselective halofunctionalizations remain poorly understood and generally applicable pr...

Full description

Saved in:
Bibliographic Details
Published in:Organic & biomolecular chemistry 2021-10, Vol.19 (38), p.837-8323
Main Authors: von der Heiden, Daniel, Németh, Flóra Boróka, Andreasson, Måns, Sethio, Daniel, Pápai, Imre, Erdelyi, Mate
Format: Article
Language:English
Subjects:
2-bis(2'-pyridylethynyl)benzene
Alkenes
Biochemistry
bonds
bromonium
Catalysts
Chelation
Chemistry
Enantiomers
Flavors
Functional materials
Halogenation
Intermediates
iodination
Iodine
Ligands
Natural products
NMR
Nuclear magnetic resonance
Organic Chemistry
organic-synthesis
Organisk kemi
participation
Pesticides
Physical and Theoretical Chemistry
Pyridines
reduction
stable carbonium-ions
Stereoselectivity
Substrates
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Enantiopure halogenated molecules are of tremendous importance as synthetic intermediates in the construction of pharmaceuticals, fragrances, flavours, natural products, pesticides, and functional materials. Enantioselective halofunctionalizations remain poorly understood and generally applicable procedures are lacking. The applicability of chiral trans -chelating bis(pyridine)iodine( i ) complexes in the development of substrate independent, catalytic enantioselective halofunctionalization has been explored herein. Six novel chiral bidentate pyridine donor ligands have been designed, routes for their synthesis developed and their [N-I-N] + -type halogen bond complexes studied by 15 N NMR and DFT. The chiral complexes encompassing a halogen bond stabilized iodenium ion are shown to be capable of efficient iodenium transfer to alkenes; however, without enantioselectivity. The lack of stereoselectivity is shown to originate from the availability of multiple ligand conformations of comparable energies and an insufficient steric influence by the chiral ligand. Substrate preorganization by the chiral catalyst appears a necessity for enantioselective halofunctionalization. The enantioselectivity of the iodine( i ) transfer process from chiral bis(pyridine)iodine( i ) complexes to alkenes is explored.
ISSN:1477-0520
1477-0539
1477-0539
DOI:10.1039/d1ob01532j