38982-12-6Relevant articles and documents
Heck Reactions of Acrolein or Enones and Aryl Bromides – Synthesis of 3-Aryl Propenals or Propenones and Consecutive Application in Multicomponent Pyrazole Syntheses
Stephan, Marvin,Panther, Jesco,Wilbert, Fabio,Ozog, Pauline,Müller, Thomas J. J.
supporting information, p. 2086 - 2092 (2020/03/23)
3-(Hetero)aryl propenals or propenones are efficiently prepared by a Heck reaction of (hetero)aryl bromides and acrolein or vinyl ketones using Beller's CataCXium Ptb ligand under Jeffery's and Fu's conditions. The formation of these three-carbon building blocks is embedded into consecutive three- and pseudo-four-component syntheses of 3-(hetero)aryl and 3,5-diarylpyrazoles with a broad substitution pattern in moderate to excellent yield.
Acrolein diethyl acetal: A three-carbon homologating reagent for the synthesis of β-arylpropanoates and cinnamaldehydes by heck reaction catalyzed by a Kaiser oxime resin derived palladacycle
Alacid, Emilio,Najera, Carmen
experimental part, p. 3102 - 3106 (2009/04/11)
A polymer palladacycle derived from Kaiser oxime resin was used as a source of palladium(0) in the chemoselective Heck reaction of acrolein diethyl acetal with aryl halides under ligand-free conditions. The use of typical Heck conditions afforded 3-arylpropionic esters, and the process can be directed to the synthesis of cinnamaldehydes under Cacchi conditions. These processes take place with rather low loading of the catalyst, which can be recovered by simple filtration and reused for at least five runs without competitive dehalogenation. This is the first time that a supported palladium complex has been reused under Cacchi conditions. ICP-OES analyses of the Pd content of the crude products in both transformations indicated lower leaching for the esters than for the aldehydes in the range up to 0.08 ppm for the esters and 0.8 ppm for the aldehydes. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
Wavelength dependent regioselective E→Z isomerization of 9-anthryldiene derivatives
Reddy, Majjigapu Janaki Ram,Kumar, Perepogu Arun,Srinivas, Uppalanchi,Reddy, Vummadi Venkat,Reddy, Maruthi Janaki Ram,Rao, G. Venugopal,Rao, Vaidya Jayathirtha
, p. 1833 - 1847 (2008/09/19)
9-Anthryldiene derivatives 1-5 are synthesized to study E→Z photoisomerization. Photoisomer composition upon direct excitation, and triplet-sensitized isomerization are determined. Quantum yield of isomerization, quantum yield of fluorescence and fluorescence life times are determined for these compounds. Interestingly, upon direct excitation the anthryldiene derivatives 1-3 carrying electron withdrawing end groups (EWG) displayed wavelength dependent regioselective E→Z isomerization from the singlet excited state. Triplet sensitization studies revealed that these anthryldiene derivatives undergo Z→E isomerization and not E→Z isomerization. The dual fluorescence observed for 1, 2, 3 and 2E, 4Z-1, indicates the involvement of two different emissive states. The fluorescence solvatochromism displayed by 1, 2, 3 and 2E, 4Z-1 is a clear indication of the involvement of a highly polarized/charge transfer singlet-excited state and the same is involved in the isomerization process. Fluorescence lifetimes measured for these compounds displayed bi-exponential behavior supporting the presence of two emissive states. A mechanism for photoisomerization is suggested.
