The unique role of fluorine in the design of active ingredients for modern crop protection

Trifluoromethylation of alkenes with concomitant introduction of additional functional groups

The trifluoromethyl group is found in many synthetic bioactive compounds, and the difunctionalization of a C=C bond, as a powerful strategy for the construction of compounds with various functional groups, has been intensively investigated. Therefore, the difunctionalizing trifluoromethylation of alkenes has attracted growing interest because of the potential of the products as building blocks for bioactive molecules. In this review, we focus on recent advances in the trifluoromethylation of alkenes with concomitant introduction of additional functional groups.

Late-Stage Fluorination: From Fundamentals to Application

In this brief account, we review work from our lab with a focus on late-stage introduction of fluorine and fluorinated functional groups into small molecules. We attempt to highlight practical developments, which we believe may have potential for industrial applications, and critically reflect on developments that may not yet meet the bar for practical use.

Asymmetric palladium-catalyzed directed intermolecular fluoroarylation of styrenes

A mild catalytic asymmetric direct fluoro-arylation of styrenes has been developed. The palladium-catalyzed three-component coupling of Selectfluor, a styrene and a boronic acid, provides chiral monofluorinated compounds in good yield and in high enantiomeric excess. A mechanism proceeding through a Pd(IV)-fluoride intermediate is proposed for the transformation and synthesis of an sp(3) C-F bond.

DABCO-catalyzed synthesis of trifluoromethylated furans from propargyl alcohols and methyl 2-perfluoroalkynoate

The DABCO-catalyzed reaction of propargyl alcohols with methyl 2-perfluoroalkynoate to give trifluoromethylated furans in up to 98% yield under mild conditions has been developed. The established allene-enol and control experiments indicate that the reaction should proceed through a Michael addition and Claisen rearrangement/cyclization process.

Solid-state NMR study of fluorinated steroids

Solid-state {(1)H}(13)C cross-polarization/magic angle spinning (CP/MAS) NMR spectroscopy was performed to analyze two fluorinated steroids, i.e., betamethasone (BMS) and fludrocortisone acetate (FCA), that have fluorine attached to C9, as well as two non-fluorinated analogs, i.e., prednisolone (PRD) and hydrocortisone 21-acetate (HCA). The (13)C signals of BMS revealed multiplet patterns with splittings of 16-215Hz, indicating multiple ring conformations, whereas the (13)C signals of FCA, HCA, and PRD exhibited only singlet patterns, implying a unique conformation. In addition, BMS and FCA exhibited substantial deviation (>3.5ppm) in approximately half of the (13)C signals and significant deviation (>45ppm) in the (13)C9 signal compared to PRD and HCA, respectively. In this study, we demonstrate that fluorinated steroids, such as BMS and FCA, have steroidal ring conformation(s) that are distinct from non-fluorinated analogs, such as PRD and HCA.

Enantioselective organocatalytic oxa-Michael addition of oximes to β-CF3-β-disubstituted nitroalkenes: efficient synthesis of β-amino-α-trifluoromethyl alcohols

An enantioselective intermolecular oxa-Michael addition of oximes to β-CF₃-β-disubstituted nitroalkenes has been developed.

Recent advances in C–H fluorination

Highlighted in this article are recent advances in C(sp²)–H and C(sp³)–H fluorination reactions.

Convergent, asymmetric synthesis of vicinal amino alcohols via Rh-catalyzed addition of α-amido trifluoroborates to carbonyls

The convergent, asymmetric synthesis of vicinal amino alcohols is achieved by the Rh-catalyzed addition of α-amido trifluoroborates to carbonyl compounds.

Copper-mediated/-catalyzed fluorination reactions: new routes to aryl fluorides

Recent advances in direct fluorination of aromatic compounds by copper catalysts have been highlighted.

Enantioselective synthesis of α,α-difluoro-β-lactams using amino alcohol ligands

A practical and highly enantioselective Reformatsky reaction of ethyl bromodifluoroacetate with imines using a cheap and commercially available amino alcohol ligand is described.