In the presence of a catalytic amount of samariumdiiodide in methylene chloride, aromatic imines react with Danishefsky diene to form tetrahydropyridine-4-ones in high yields. Under the same conditions, various imino-aldol reactions afford β-amino esters or β-amino ketones.
A simple ketone as an efficient metal-free catalyst for visible-light-mediated Diels–Alder and aza-Diels–Alder reactions
作者:Jiri Kollmann、Yu Zhang、Waldemar Schilling、Tong Zhang、Daniel Riemer、Shoubhik Das
DOI:10.1039/c9gc00485h
日期:——
Diels–Alder reactions are highly effective between electron-rich dienes and electron-poor dienophiles. However, these reactions with electron-rich dienophiles are limited and require forcing conditions. Based on this, an efficientmetal-free homogeneous system has been developed for the Diels–Alder reactions between electron-rich dienophiles and dienes under visible-light conditions. Additionally,
loss in efficiency. The reactions between N-benzylideneanilines and Danishefsky’s diene proceed smoothly in acidic aqueousmedium in the presence of a catalytic amount of copper(II) triflate–sodium dodecyl sulfate [Cu(OTf)2–SDS] to afford the corresponding 1,2-diphenyl-2,3-dihydro-4-pyridones in excellent yields of 84–95%. The aqueoussolutioncontaining the catalyst is recovered and reused without any
Post‐Synthetic Modification of Metal‐Organic Frameworks Bearing Phenazine Radical Cations for aza‐Diels‐Alder Reactions
作者:Wei‐Ling Jiang、Bin Huang、Meng‐Xiang Wu、Ye‐Kai Zhu、Xiao‐Li Zhao、Xueliang Shi、Hai‐Bo Yang
DOI:10.1002/asia.202100883
日期:2021.12
Herein a novel MOF R containing phenazineradical cations was synthesized by a post-synthetic modification strategy. It showed excellent stability according to the tests of XRD and EPR. Moreover, MOF R could be employed as a recyclable, stable and efficient heterogeneous catalyst for aza-Diels-Alder reactions.
as the halogenbondcatalyst. The desired [4+2] cycloaddition products, bearing aryl, heteroaryl, alkyl, and alicyclic substituents, were successfully furnished in 28–99% yields. Mechanistic investigations proved that a strong halogen-bonding interaction forged between the iodopyridinium catalyst and imine intermediate was essential to dynamically masking the vulnerable C–I bond on the catalyst and accelerating