singlet oxygen as an oxidizer and the reaction is specific to distorted aromatic systems. The versatility of the prepared diketones and tetraketones was proven in several heterocycle-forming reactions. The observed adjustment of the physicochemicalproperties of original molecules is valuable for further development of functional molecules based on helicenes.
作者:Martin Jakubec、Indrajit Ghosh、Jan Storch、Burkhard König
DOI:10.1002/chem.201904169
日期:2020.1.7
Herein, a visible-light photochemical approach for practical helicene functionalization at very mild reaction conditions is described. The photochemical reactions allow for the regiospecific and innate late-stage functionalization of helicenes and are easily executed either through the activation of C(sp2 )-Br bonds in helicenes using K2 CO3 as inorganic base or direct C(sp2 )-H helicene bond functionalization
作者:Mourad Ben Braiek、Faouzi Aloui、Béchir Ben Hassine
DOI:10.1016/j.tetlet.2012.11.036
日期:2013.1
2-Hydroxyhexahelicene has been prepared in good yield and purity via a three-step sequence involving palladium-catalysed Heck coupling and classical oxidative photocyclisation reactions. The two enantiomers of this hexacyclic helicenol have been separated using (S)-(-)-camphanoyl chloride as the chiral resolving agent. (C) 2012 Elsevier Ltd. All rights reserved.
BROWN, J. M.;FIELD, I. P.;SIDEBOTTOM, P. J., TETRAHEDRON LETT., 1981, 22, N 48, 4867-4870