5782-20-7Relevant academic research and scientific papers
Predicting the Outcome of Photocyclisation Reactions: A Joint Experimental and Computational Investigation
Wonanke, A. D. Dinga,Ferguson, Jayne L.,Fitchett, Christopher M.,Crittenden, Deborah L.
, p. 1293 - 1303 (2019)
Photochemical oxidative cyclodehydrogenation reactions are a versatile class of aromatic ring-forming reactions. They are tolerant to functional group substitution and heteroatom inclusion, so can be used to form a diverse range of extended polyaromatic systems by fusing existing ring substituents. However, despite their undoubted synthetic utility, there are no existing models—computational or heuristic—that predict the outcome of photocyclisation reactions across all possible classes of reactants. This can be traced back to the fact that “negative” results are rarely published in the synthetic literature and the lack of a general conceptual framework for understanding how photoexcitation affects reactivity. In this work, we address both of these issues. We present experimental data for a series of aromatically substituted pyrroles and indoles, and show that quantifying induced atomic forces upon photoexcitation provides a powerful predictive model for determining whether a given reactant will photoplanarise and hence proceed to photocyclised product under appropriate reaction conditions. The propensity of a molecule to photoplanarise is related to localised changes in charge distribution around the putative forming ring upon photoexcitation. This is promoted by asymmetry in molecular structures and/or charge distributions, inclusion of heteroatoms and ethylene bridging and well-separated or isolated photocyclisation sites.
Rhodium(iii)-catalyzed indole synthesis at room temperature using the transient oxidizing directing group strategy
Shang, Yaping,Jonnada, Krishna,Yedage, Subhash Laxman,Tu, Hua,Zhang, Xiaofeng,Lou, Xin,Huang, Shijun,Su, Weiping
supporting information, p. 9547 - 9550 (2019/08/15)
Rh-catalyzed reactions of N-alkyl anilines with internal alkynes at room temperature have been developed using an in situ generated N-nitroso group as a transient oxidizing directing group. Due to mild reaction conditions, this method enabled synthesis of a broad range of N-alkyl indoles, including even two indole-based medicinal compounds. Our work disclosed the feasibility of the transient oxidizing directing group strategy in C-H functionalization reactions, which possesses the potential to enhance overall step-economy and impart new reactivity patterns to substrates.
Rhodium-catalyzed annulation of tertiary aniline N-oxides to N-alkylindoles: Regioselective C-H activation, oxygen-atom transfer, and N-dealkylative cyclization
Li, Bin,Xu, Hong,Wang, Huanan,Wang, Baiquan
, p. 3856 - 3862 (2016/07/06)
[Cp?RhIII]-catalyzed annulation of tertiary aniline N-oxides with alkynes was reported to achieve the challenging ortho C-H functionalization of tertiary anilines via N-O bond acting as a traceless directing group. More significantly, this system represents the first example which integrates C-H activation, oxygen-atom transfer, and N-dealkylative cyclization in one reaction. This unprecedented coupling reaction has allowed the construction of N-alkylindole derivatives in high efficiency with broad substrate scope and good functional group tolerance.
Ultrasound-promoted synthesis of 2,3-bis(4-hydroxyphenyl)indole derivatives as inherently fluorescent ligands for the estrogen receptor
Koulocheri, Sophia D.,Haroutounian, Serkos A.
, p. 1723 - 1729 (2007/10/03)
A series of 2,3-bis(4-hydroxyphenyl)indole derivatives 4c-f was prepared by ultrasound-promoted intramolecular cyclodehydration of a polyphosphoric acid solution of α-anilinyl-(or 3-anisidyl)desoxyanisoins 2c-f, and their optical spectroscopy and estrogen receptor (ER) binding properties were studied. Compounds 4c-f give intense long-wavelength fluorescent emission, sensitive to solvent polarity and pH. Furthermore, the two indol-6-ols 4e, f display reasonably good binding affinities to ER and appear to be well suited for use as fluorescent probes for the detection of ER in cells.
