Synthesis of a new pinacolacetal-phosphonium salt and its reaction with aldehydes to give homologated acetals and two-carbon homologated unsaturated aldehydes is presented. The chemistry takes place in water under mild conditions and the sequence can be performed in one-flask operation.
The Heckarylation of acrolein with a variety of condensed aryl and heteroaryl halides is described. Depending on the substrate, up to 87% isolated yield to the expected aldehydes was achieved. When the reaction was run on diethylacetal acrolein, the choice of catalytic system dramatically affected the selectivity of the reaction: the catalyst system based on Herrmann’s palladacycle complex gave mainly
Self-Assembly of “Chalcone” Type Push-Pull Dye Molecules into Organic Single Crystalline Microribbons and Rigid Microrods for Vis/NIR Range Photonic Cavity Applications
fluorescent donor–acceptor typedyemolecule, (2E,4E)‐1‐(2‐hydroxyphenyl)‐5‐(pyren‐1‐yl)penta‐2,4‐dien‐1‐one (HPPD) self‐assembles in a mixture of ethanol/chloroform through intermolecular π–π stacking (distance ca. 3.384 Å) to form J‐aggregated single‐crystallinemicroribbons displaying Fabry–Pèrot (F‐P) type visible‐range optical resonance. The corresponding borondifluoride dye (HPPD‐BF), with a reduced
A heterogeneous tetrakis(ammine)palladium-NaY zeolite [Pd(NH3)4]/NaY} catalyst was applied successfully to the Heckarylation of acroleindiethylacetal using a large variety of aryl and heteroaryl bromides. Depending on the reaction conditions (Heck versus Cacchi) good to high selectivities toward the 3-arylpropionicesters or to the cinnamaldehydes were achieved, respectively. Under classical Heck
Combining iminium and supramolecular catalysis for the [4 + 2] cycloaddition of <i>E</i>-cinnamaldehydes
作者:Kendra K. Shrestha、Michael A. Hilyard、Indunil Alahakoon、Michael C. Young
DOI:10.1039/d2ob01171a
日期:——
Herein we describe a method for combining supramolecularcatalysis with imininum-based organocatalysis in the Diels–Alder cycloaddition reaction. Both supramolecular host and L-proline are required for the reaction to occur, implying that encapsulation of the substrates and co-catalyst are necessary for the reaction to occur. We explore the substrate scope for a variety of E-cinnamaldehydes and dienes