Synthesis of 2-Phospha[7]helicene

0573819 - ÚCHP 2024 CZ eng A - Abstract
Beránek, Tomáš - Jakubec, Martin - Sýkora, Jan - Žádný, Jaroslav - Storch, Jan
Synthesis of 2-Phospha[7]helicene.
Book of Abstracts. 2023. s. 73, č. článku Poster P-3..
[International Symposium on the Synthesis and Applications of Curved Organic π-Molecules and Materials /5./. 19.07.2023-21.07.2023, Prague]
R&D Projects: GA MV(CZ) VJ01010065
Institutional support: RVO:67985858
Keywords : phosphahelicenes * phosphinine * phosphorus
OECD category: Organic chemistry

Helical polyaromatic compounds, helicenes, attract attention due to their extraordi-nary optoelectronic properties, which predestine them for applications in the field of materials science. However, the ideal properties are rarely found in unsubstituted carbohelicenes, and therefore their further modification is necessary. The incorporation of a phosphorus cycle offers several beneficial aspects, such as the introduction of a stable chiral centre on the phosphorus atom, easy variation of its oxidation state and the possibility of further derivatisa-tion, including the formation of metal complexes. This versatility then allows the molecule to be ideally adapted to its intended application. In this context, a synthetic strategy towards phosphahelicenes containing a terminal phosphinine ring was explored. After many unsuccessful attempts, a simple synthetic route was successfully developed. Finally, the 4-phenyl-6-methyl-2- phospha[7]helicene was pre-pared in 12 steps from the starting 2- bromobenzo[c]phenanthrene in 12% overall yield. The synthetic approach involves the introduction of the phosphorus function prior to photocycliza-tion to form the final helicene skeleton, followed by the formation of a phosphorus hexacycle. The structure of the first phosphahelicene with a terminal phosphinine ring was confirmed by X-ray crystallography. The aromatic character of the phosphinine ring and its conjugation to the helicene moiety were deduced from DFT calculations and the physico-chemical proper-ties of the target molecule.
Permanent Link: https://hdl.handle.net/11104/0344173