Topic
Annulation
About: Annulation is a research topic. Over the lifetime, 10152 publications have been published within this topic receiving 189701 citations.
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TL;DR: This work has demonstrated that NHC-catalyzed reactions of C-C unsaturated bonds are feasible, including the umpolung of Michael acceptors, the Morita-Baylis-Hillman reaction, and the annulation reactions of vinyl sulfones, nitroalkenes, allenoates and alkynes.
Abstract: The N-heterocyclic carbene-catalyzed reactions of C-X (X = O, S, N) unsaturated bonds are well established. However, C-C unsaturated bonds are challenging substrates for NHC-catalyzed reactions. In recent years, several reports have demonstrated that NHC-catalyzed reactions of C-C unsaturated bonds are feasible, including the umpolung of Michael acceptors, the Morita-Baylis-Hillman reaction, and the annulation reactions of vinyl sulfones, nitroalkenes, allenoates and alkynes.
71 citations
TL;DR: The first catalytic enantioselective [4 + 3] annulation of allenoates with C,N-cyclic azomethine imines is developed, which works efficiently under mild reaction conditions to afford seven-membered ring-fused quinazoline-based tricyclic heterocycles in high yields with good to excellent diastereo- and enantiOSElectivities.
71 citations
TL;DR: A catalytic method for the asymmetricannulation of Morita–Baylis–Hillman carbonates with trifluoroethylidenemalonates has been developed, affording highly functionalized trifLUoromethyl-bearing cyclopentenes in excellent yields, high diastereoselectivities and enantioselectivity under mild conditions.
Abstract: On the basis of the design and synthesis of multifunctional thiourea-phosphines, a catalytic method for the asymmetric [3+2] annulation of Morita–Baylis–Hillman carbonates with trifluoroethylidenemalonates has been developed, affording highly functionalized trifluoromethyl-bearing cyclopentenes in excellent yields, high diastereoselectivities and enantioselectivities under mild conditions.
71 citations
TL;DR: A mechanistic investigation reveals that the sequential annulations involved an unprecedented stepwise [3+2+2]-cycloaddition.
71 citations
TL;DR: The first chiral phosphine-catalyzed activation of acrylates for intramolecular formal [2 + 4] reactions with unsaturated imines is described, which afford N-heterocycles with exceptionally high diastereo- and enantioselectivities.
71 citations