School of Chemistry & Molecular Bioscience, Molecular Horizons, Illawarra Health & Medical Research Institute, University of Wollongong, Northfields Avenue, 2522, Wollongong, NSW, Australia.
Department of Chemistry and Pharmacy, Computer-Chemistry-Center (CCC), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Nägelbachstrasse 25, 91052, Erlangen, Germany.
Chemistry. 2021 Feb 19;27(11):3708-3721. doi: 10.1002/chem.202003662. Epub 2021 Feb 12.
The synthesis of structurally diverse heterocycles for chemical space exploration was achieved via the cascade reactions of indigo with propargylic electrophiles. New pyrazinodiindolodione, naphthyridinedione, azepinodiindolone, oxazinoindolone and pyrrolodione products were prepared in one pot reactions by varying the leaving group (-Cl, -Br, -OMs, -OTs) or propargyl terminal functionality (-H, -Me, -Ph, -Ar). Mechanistic and density functional theory studies revealed that the unsaturated propargyl moiety can behave as an electrophile when aromatic terminal substitutions are made, and therefore competes with leaving group substitution for new outcomes. Selected products from the cascade reactions were investigated for their absorption and fluorescence properties, including transient absorption spectroscopy. This revealed polarity dependent excited state relaxation pathways, fluorescence, and triplet formation, thus highlighting these reactions as a means to access diverse functional materials rapidly.
通过靛红与丙炔基亲电试剂的级联反应，实现了用于化学空间探索的结构多样杂环的合成。通过改变离去基团（-Cl、-Br、-OMs、-OTs）或丙炔基末端官能团（-H、-Me、-Ph、-Ar），一锅反应制备了新的吡嗪二吲哚二酮、萘啶二酮、氮杂环庚二酮、恶唑并吲哚啉酮和吡咯二酮产物。机理和密度泛函理论研究表明，当芳基末端取代时，不饱和丙炔部分可以作为亲电试剂，因此与离去基团取代竞争新产物。对级联反应的部分产物进行了吸收和荧光性质的研究，包括瞬态吸收光谱。这揭示了依赖于极性的激发态弛豫途径、荧光和三重态形成，从而突出了这些反应作为快速获得多种功能材料的一种手段。
