A Rh-catalyzed domino synthesis of 4-hydroxy-3-methylcoumarins via branch-selective hydroacylation of acrylates and acrylamides using salicylaldehydes is described. This protocol under phosphine-free Rh-catalyzed conditions provided 4-hydroxy-3-methylcoumarins in high yields with excellent functional group tolerance and high selectivity.
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http://dx.doi.org/10.1039/c9ob01972c | DOI Listing |
J Org Chem
April 2024
Department of Chemistry, National Chung-Hsing University, Taichung 402202, Taiwan, R.O.C.
A stereodivergent approach toward total syntheses of alkaloids 223A and 6--223A is described. The approach features a concise construction of an indolizidine skeleton by Rh-catalyzed domino hydroformylation double cyclization and sequential stereocontrolled transformations such as reductive alkylation or -selective α-alkylation of the 5-oxoindolizidine. These stereoselective reactions afford the desired stereochemistry in the targets.
View Article and Find Full Text PDFChem Asian J
March 2024
Department of Chemistry, National Chung Hsing University, 250 Kuokuang road, Taichung, 402, Taiwan, R.O.C.
A one-pot route to a novel azepane-fused tetrahydro-β-carboline framework from tryptyl-4-pentenamide derivatives has been developed, featuring the Rh-catalyzed hydroformylation double cyclization. Subsequent alkylation in the tetracyclic system proceeded stereoselectively to form a quaternary carbon. The synthesis of (±)-20-epi-kopsiyunnanine K was accomplished through the strategy.
View Article and Find Full Text PDFChemistry
November 2021
State Key Laboratory of Structural Chemistry, Center for Excellence in Molecular Synthesis, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Yangqiao West Road 155, Fuzhou, Fujian, 350002, China.
The Rh-catalyzed ortho-C(sp )-H functionalization of 8-aminoquinoline-derived benzamides with aliphatic acyl fluorides generated in situ from the corresponding acids has been developed. This reaction initiated with 8-aminoquinoline-directed ortho-C(sp )-H acylation, which was accompanied by subsequent intramolecular nucleophilic acyl substitution of amide group to produce alkylidene phthalides This approach exhibits high stereo-selectivity for Z-isomer products, and tolerates a variety of functional groups as well as aliphatic carboxylic acids with diverse structural scaffolds.
View Article and Find Full Text PDFOrg Biomol Chem
January 2021
Department of Chemistry, Rice University, 6500 Main Street, Houston, Texas 77030, USA.
A mild Rh-catalyzed method for synthesis of cyclic unprotected N-Me and N-H 2,3-aminoethers using an olefin aziridination-aziridine ring-opening domino reaction has been developed. The method is readily applicable to the stereocontrolled synthesis of a variety of 2,3-disubstituted aminoether O-heterocyclic scaffolds, including tetrahydrofurans, tetrahydropyrans and chromanes.
View Article and Find Full Text PDFACS Omega
February 2020
Department of Chemistry, National Chung Hsing University, 250 Kuokuang Road, Taichung 402, Taiwan, R.O.C.
Here, we describe the recent progress toward construction of 1-azabicyclic structures using a domino hydroformylation double cyclization strategy of an amide bearing the trisubstituted alkene functionality. The method provides a rapid and atom-economic access to alkaloid structures under mild conditions, especially for quinolizidine and pyrrolidine-fused azepane skeletons with yields up to 82% and good diastereoselectivity. Subsequent oxidative cleavage conditions are developed for the synthesis of alkaloid epi-epiquinamide.
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