A novel and highly efficient synthetic approach to pyrroloindolines has been developed. The process is based on tandem radical addition/cyclization with inexpensive iron catalyst. This method tolerates a wide range of N-methyl-N-arylacrylamides as well carbamoyl radicals, providing access to a variety of functionalized 3,3-disubstituted oxindoles, key intermediates for many bioactive pyrroloindolines such as (±)-esermethole, (±)-deoxyeseroline, and (±)-physovenol methyl ether.
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http://dx.doi.org/10.1021/acs.orglett.7b00078 | DOI Listing |
Molecules
January 2025
Department of Chemistry, Fudan University, Shanghai 200438, China.
This review highlights significant advances in iron-catalyzed cross-dehydrogenative coupling (CDC), a method pivotal for forming carbon-carbon (C-C) bonds directly from C-H bonds. This technique uses iron-a naturally abundant, inexpensive, and environmentally benign transition metal-as a catalyst to facilitate the coupling of two unfunctionalized C-H bonds. This method stands out for avoiding pre-functionalized substrates, reducing both waste and cost in organic synthesis.
View Article and Find Full Text PDFJ Am Chem Soc
December 2024
Merck Center for Catalysis at Princeton University, Princeton, New Jersey 08544, United States.
Quaternary carbon centers are desirable targets for drug discovery and complex molecule synthesis, yet the synthesis of these motifs within traditional cross-coupling paradigms remains a significant challenge due to competing β-hydride elimination pathways. In contrast, the bimolecular homolytic substitution (S2) mechanism offers a unique and attractive alternative pathway. Metal porphyrin complexes have emerged as privileged catalysts owing to their ability to selectively form primary metal-alkyl complexes, thereby eliminating the challenges associated with tertiary alkyl complexation with a metal center.
View Article and Find Full Text PDFJ Org Chem
December 2024
Department of Chemistry, Fudan University, 2005 Songhu Road, Shanghai, 200438, China.
An iron-catalyzed nitrene transfer reaction for the rapid synthesis of sulfinamidines from readily available sulfenamides is reported. This method features mild conditions, short reaction times, and a broad substrate scope, allowing the preparation of a variety of sulfinamidines in good to excellent yields. The synthetic utility of the sulfinamidine products was further demonstrated through their conversion to other valuable sulfur(VI) compounds, such as sulfondiimidoyl fluorides, sulfinamidiate esters, and sulfonimidamides.
View Article and Find Full Text PDFOrg Lett
November 2024
Key Laboratory of Jiangxi Province for Persistent Pollutants Prevention Control and Resource Reuse, Nanchang Hangkong University, Nanchang 330063, China.
A new iron-catalyzed three-component perfluoroalkylarylation of styrenes with alkyl halides and arenes has been established. Alkyl halides undergo halogen atom transfer with methyl radicals to form alkyl radicals in reactions initiated by a combination of -butyl peroxybenzoate and an iron catalyst, thus adducting to the olefins, which results in alkylarylation products. The protocol is compatible with a wide range of perfluoroalkyl and non-perfluoroalkyl halides, features excellent functional group tolerance, and enables the synthesis of structurally diverse 1,1-diaryl fluoro-substituted alkanes.
View Article and Find Full Text PDFACS Catal
September 2024
Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States.
The synthesis and application of aryl-substituted pyridine(diimine) iron complexes (PDI)FeCH to the catalytic borylation of heteroarenes under thermal conditions is described. Improvements in catalyst design and performance were guided by precatalyst activation studies, where investigations into stoichiometric reactivities of iron borohydride (4- Bu- PDI)Fe(HBPin) and iron furyl (4- Bu- PDI)Fe(2-methylfuryl) complexes revealed facile C(sp)-H activation and a slower and potentially turnover-limiting C(sp)-B formation step. Formation of the flyover dimer, [(4- Bu- PDI)Fe] was identified as a catalyst deactivation pathway and formally iron(0) complexes were found to be inactive for borylation.
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