Dynamic Covalent Chemistry Approach toward 18-Membered P4N2 Macrocycles and Their Nickel(II) Complexes

Elvira I Musina; Tatiana I Wittmann; Lenar I Musin; Anna S Balueva; Alena S Shpagina; Igor A Litvinov; Peter Lönnecke; Evamarie Hey-Hawkins; Andrey A Karasik; Oleg G Sinyashin

doi:10.1021/acs.joc.0c01317

Dynamic Covalent Chemistry Approach toward 18-Membered P₄N₂ Macrocycles and Their Nickel(II) Complexes

J Org Chem. 2020 Nov 20;85(22):14610-14618. doi: 10.1021/acs.joc.0c01317. Epub 2020 Oct 5.

Affiliations

¹ Arbuzov Institute of Organic and Physical Chemistry, FRC Kazan Scientific Center, Russian Academy of Sciences, 420088 Kazan, Russian Federation.
² Faculty of Chemistry and Mineralogy, Institute of Inorganic Chemistry, Leipzig University, Leipzig 04109, Germany.

PMID: 32967420
DOI: 10.1021/acs.joc.0c01317

Abstract

A dynamic covalent chemistry approach was used for the stereoselective synthesis of 1,10-diaza-3,8,12,17-tetraphosphacyclooctadecanes via condensation reaction of 1,4-bis(organylphosphino)butane, formaldehyde, and primary amines. The obtained 18-membered P₄N₂ macrocycles were isolated in pure form as meso- (R_PS_PS_PR_P) or rac- (R_PR_PR_PR_P/S_PS_PS_PS_P) isomers. The structural features of the individual stereoisomers were revealed by NMR spectroscopy and X-ray structure analysis. All P₄N₂ macrocycles form square-planar nickel(II) complexes with the R_PS_PS_PR_P isomer only, in which the orientation of the lone pairs of electrons at phosphorus favors this coordination mode, independent of the initial configuration of the ligand, indicating the ability of the 18-membered P₄N₂ macrocycles to stereoisomerize in the course of the complexation.