Deltoid versus Rhomboid: Controlling the Shape of Bis-ferrocene Macrocycles by the Bulkiness of the Substituents
摘要:
Precise structural control of heteroannularly disubstituted ferrocene (Fc) structures is very challenging as the high rotational mobility of the Fc unit allows a large conformational diversity. Herein we present the syntheses, characterization, and electrochemical investigation of two complementary bis-ferrocene macrocycles, built up via Sonogashira cross coupling and intramolecular ring-closing reaction. While the X-ray structure of 1,2-ethynylbenzene bridged bis-ferrocene complex 1 shows a deltoidal conformation, a stretched oriented rhomboidal bis-ferrocene metalla-cycle 2 is formed when the peripheral benzene rings are decorated with bulky tert-butylsulfanyl groups. VT-NMR spectroscopy is used to assign the rotation of the embedded Fc units in rhomboid 2. Moreover, cyclic voltammetry (CV) of deltoid 1 and rhomboid 2 indicate that electronic communication between both ferrocenyl groups can be neglected, while the electrostatic through space coupling is significant.
A C‐3 thiocyanation of 2‐aryl‐quinolin‐4‐ones in the presence of eosin‐Y and visible light has been developed. The methodology allows easy access to a variety of 2‐aryl‐3‐thiocyano‐quinolin‐4‐ones in moderate to high yields. Regioselective para‐thiocyanation of anilines has also been achieved under these conditions. The reaction is operationally simple, metal‐free, requires air as the oxidant, and proceeds smoothly at room temperature.
AlCl<sub>3</sub>-Promoted Thiocyanation of <i>N</i>-Containing Aromatic and Heteroaromatic Compounds Under Solvent-Free Conditions
作者:Kobra Nikoofar、Samareh Gorji
DOI:10.1080/10426507.2014.978321
日期:2015.7.3
Aluminum chloride/Ammonium thiocyanate (AlCl3/NH4SCN) was found to be an effective system for the thiocyanation of some arylamines and indoles to afford the corresponding thiocyanated adducts at room temperature under solvent-free conditions. The efficacy of this combined reagent was also examined in the thiocyanation of pyrrole and isatin. A plausible mechanism of thiocyanation has also been suggested.