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: A novel [3 + 2] annulation between para-quinone methides and vinylcyclopropanes for the synthesis of spiro[4.5]deca-6,9-diene-8-ones has been described and the reaction exhibited good functional group tolerance and scalability.
120 citations
TL;DR: The formation of large π-conjugated systems on the organic linker dramatically enhanced the photoresponsive properties of PCN-136, which was employed as an inherent photocatalytic system for CO2 reduction under visible-light irradiation, which showed increased activity compared with pbz-MOF-1.
Abstract: The incorporation of large π-conjugated ligands into metal-organic frameworks (MOFs) can introduce intriguing photophysical and electrochemical properties into the framework. However, these effects are often hindered by the strong π-π interaction and the low solubility of the arylated ligands. Herein, we report the synthesis of a porous zirconium-based MOF, Zr6(μ3-O)4(μ3-OH)4(OH)6(H2O)6(HCHC) (PCN-136, HCHC = hexakis(4-carboxyphenyl)hexabenzocoronene), which is composed of a hexacarboxylate linker with a π-conjugated hexabenzocoronene moiety. Direct assembly of the Zr4+ metal centers and the HCHC ligands was unsuccessful due to the low solubility and the unfavorable conformation of the arylated HCHC ligand. Therefore, PCN-136 was obtained from aromatization-driven postsynthetic annulation of the hexaphenylbenzene fragment in a preformed framework (pbz-MOF-1) to avoid π-π stacking. This postsynthetic modification was done through a single-crystal-to-single-crystal transformation and was clearly observable utilizing single -crystal X-ray crystallography. The formation of large π-conjugated systems on the organic linker dramatically enhanced the photoresponsive properties of PCN-136. With isolated hexabenzocoronene moieties as photosensitizers and Zr-oxo clusters as catalytic sites, PCN-136 was employed as an inherent photocatalytic system for CO2 reduction under visible-light irradiation, which showed increased activity compared with pbz-MOF-1.
120 citations
TL;DR: A new class of pyrroloisoquinoline alkaloid, isolamellarin, was synthesized based on the annulation of dihydroisoquinoline with aryl pyruvates under basic condition and Cu-mediated/MW-assisted C-O(carboxylic) lactonization.
Abstract: A simple and highly effective C−Ocarboxylic coupling reaction catalyzed by copper(I) salts has been developed to synthesize benzopyranones. The reaction of various 2-halobiarylcarboxylic acids was examined using microwave irradiation. A new class of pyrroloisoquinoline alkaloid, isolamellarin, was synthesized based on the annulation of dihydroisoquinoline with aryl pyruvates under basic condition and Cu-mediated/MW-assisted C−Ocarboxylic lactonization.
120 citations
TL;DR: Using rhodium-catalyzed sequential oxidative C-H annulation reaction between ketazines and internal alkynes, both N-atoms of the azines could be efficiently incorporated to the desired isoquinolines under very robust and mild reaction conditions.
120 citations