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Abstract The electrochemical generation of vinyl carbocations from alkenyl boronic esters and boronates is reported. Using easy‐to‐handle nucleophilic fluoride reagents, these intermediates are trapped to form fully substituted vinyl fluorides. Mechanistic studies support the formation of dicoordinated carbocations through sequential single‐electron oxidation events. Notably, this electrochemical fluorination features fast reaction times and Lewis acid‐free conditions. This transformation provides a complementary method to access vinyl fluorides with simple fluoride salts such as TBAF.
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This content will become publicly available on February 1, 2026
Enantioconvergent nucleophilic substitution via synergistic phase-transfer catalysis
Abstract Catalytic enantioconvergent nucleophilic substitution reactions of alkyl halides are highly valuable transformations, but they are notoriously difficult to implement. Specifically, nucleophilic fluorination is a renowned challenge, especially when inexpensive alkali metal fluorides are used as fluorinating reagents due to their low solubility, high hygroscopicity and Brønsted basicity. Here we report a solution by developing the concept of synergistic hydrogen bonding phase-transfer catalysis. Key to our strategy is the combination of a chiralbis-urea hydrogen bond donor (HBD) and an onium salt—two phase-transfer catalysts essential for the solubilization of potassium fluoride—as a well-characterized ternary HBD–onium fluoride complex. Mechanistic investigations indicate that this chiral ternary complex is capable of enantiodiscrimination of racemic benzylic bromides and α-bromoketones, and upon fluoride delivery affords fluorinated products in high yields and enantioselectivities. This work provides a foundation for enantioconvergent fluorination chemistry enabled through the combination of a HBD catalyst with a co-catalyst specifically curated to meet the requirement of the electrophile.
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- Award ID(s):
- 2400056
- PAR ID:
- 10593207
- Publisher / Repository:
- Springer Nature
- Date Published:
- Journal Name:
- Nature Catalysis
- Volume:
- 8
- Issue:
- 2
- ISSN:
- 2520-1158
- Page Range / eLocation ID:
- 107 to 115
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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