Asymmetric Fluorofunctionalizations with Carboxylate‐Based Phase‐Transfer Catalysts

• Published in: Chemical record Vol. 23; no. 7; pp. e202200285 - n/a
• Main Authors: Egami, Hiromichi, Hamashima, Yoshitaka
• Format: Journal Article
• Language: English
• Published: United States Wiley Subscription Services, Inc 01.07.2023
• Subjects: Agrochemicals; Alkenes; asymmetric reaction; Asymmetry; Carboxylic acids; Catalysts; dearomatization; difunctionalization; Enantiomers; Fluorination; Fluorine; Indoles; Nucleophiles; Organic chemistry; Phase transfer catalysts; phase-transfer catalyst; Reagents; fluorination; difunctionalization; asymmetric reaction; phase-transfer catalyst; dearomatization
• ISSN: 1527-8999; 1528-0691; 1528-0691
• DOI: 10.1002/tcr.202200285

Fluorine is an attractive element in the field of pharmaceutical and agrochemical chemistry due to its unique properties. Considering the chiral environment in nature, where enantiomers often show different biological activities, the introduction of fluorine atom(s) into organic molecules to make chiral fluorinated compounds is an important subject. Herein, we describe the story of the development of our chiral carboxylate‐based phase‐transfer catalysts and their applications for asymmetric fluorocyclizations of alkenes bearing a carboxylic acid, an amide, and an oxime as an internal nucleophile with a dicationic fluorinating reagent, Selectfluor. We also describe dearomative fluorinations of indole derivatives, 2‐naphthols, and resorcinols. This personal account describes the design and synthesis of novel carboxylate‐based phase‐transfer catalysts for fluorination with Selectfluor. The catalysts enable various enantioselective fluorofunctionalizations of alkene derivatives and (hetero)aromatic compounds. The advantages of our catalytic system, its synthetic utility, and detailed mechanistic studies uncovering a unique catalytic cycle are also discussed briefly.