1123745-75-4Relevant academic research and scientific papers
Gold(I)-Catalyzed Intramolecular Hydroarylation of Phenol-Derived Propiolates and Certain Related Ethers as a Route to Selectively Functionalized Coumarins and 2 H-Chromenes
Cervi, Aymeric,Vo, Yen,Chai, Christina L. L.,Banwell, Martin G.,Lan, Ping,Willis, Anthony C.
, p. 178 - 198 (2020/12/22)
Methods are reported for the efficient assembly of a series of phenol-derived propiolates, including the parent system 56, and their Au(I)-catalyzed cyclization (intramolecular hydroarylation) to give the corresponding coumarins (e.g., 1). Simple syntheses of natural products such as ayapin (144) and scoparone (145) have been realized by such means, and the first of these subject to single-crystal X-ray analysis. A related process is described for the conversion of propargyl ethers such as 156 into the isomeric 2H-chromene precocene I (159), a naturally occurring inhibitor of juvenile hormone biosynthesis.
How much does the hybridization of a carbon atom affect the transmission of the substituent effect on the chemical shift?
Jeong, Eun Jeong,Lee, In-Sook Han
, p. 295 - 299 (2015/03/03)
1H and 13C NMR spectra of aryl esters of propionic acid, acrylic acid, and propiolic acid were systematically examined to find out the substituent effect on the chemical shift. The values of the chemical shift of the carbonyl carbon showed an inverse correlation with the Hammett ?3 values, and the magnitude of the slope was the largest with the propiolates. The ?± carbons of acrylates and propiolates also showed an inverse correlation with much smaller values of the slopes than those of the carbonyl carbons; but those of the propionates showed absolutely no correlation. However, the ?2 carbons of acrylates and propiolates showed normal correlation with larger values of the slopes. The signs and the magnitudes of the slopes may be understood by the transmission of the substituent electronic effect through bonds as well as through space. The propiolyloxy group also showed a significantly large effect on the 13C chemical shift values of the benzene ring.
A new gold-catalyzed domino cyclization and oxidative coupling reaction
Wegner, Hermann A.,Ahles, Sebastian,Neuburger, Markus
supporting information; experimental part, p. 11310 - 11313 (2009/10/17)
Gold-catalyzed domino cyclization and oxidative coupling reaction for synthesis of dicoumarins was studied. Gold was thought to be an unreactive metal before its catalyzed reaction was discovered. HAuCl4 was suspended in dry 1,2-dichloroethane (DCE), whereas protic solvent gave only monomer and UV absorption and fluorescence properties of dicoumarins were similar to those of monomers. The crude product was purified by flash column chromatography on silica and gold catalyst performed two different functions. Dicoumarins, scaffolds of natural products has interesting biological properties whereas, potential photostable UV-absorbent materials were accessed in two steps from commercially available starting materials. The reaction generally proceeded in moderate-to-good yields, tolerating a variety of substituents on the aromatic moiety.
