Synthetic approach to borrelidin fragments: focus on key intermediates

• Yudhi Dwi Kurniawan,
• Zetryana Puteri Tachrim,
• Teni Ernawati,
• Faris Hermawan,
• Ima Nurasiyah and
• Muhammad Alfin Sulmantara

Beilstein J. Org. Chem. 2025, 21, 1135–1160, doi:10.3762/bjoc.21.91

• constructing Omura’s C1–C11 fragment Yadav and Yadav, in 2013, reported their work on preparing the C1–C11 fragment 61 of borrelidin. Their approach employed an iterative sequence of oxidation, Wittig olefination, hydrogenation, and asymmetric methylation for carbon homologation, alongside Sharpless

• ’ amide, and asymmetric methylation. Intermediate 65, in turn, would be obtained from the known five-carbon precursor 66 through the iterative sequence of oxidation, Wittig olefination, hydrogenation, asymmetric methylation, followed by reduction of the carboxyl group and protection of the resulting

• of the target molecule. Another series of oxidation, Wittig olefination, reduction, and asymmetric methylation was applied to the right-hand side of compound 65, affording compound 76. This transformation added two carbons to the backbone and introduced a methyl branch with the correct

Copper-catalyzed asymmetric methylation of fluoroalkylated pyruvates with dimethylzinc

• Kohsuke Aikawa,
• Kohei Yabuuchi,
• Kota Torii and
• Koichi Mikami

Beilstein J. Org. Chem. 2018, 14, 576–582, doi:10.3762/bjoc.14.44

• Kohsuke Aikawa Kohei Yabuuchi Kota Torii Koichi Mikami Department of Chemical Science and Engineering, School of Materials and Chemical Technology, Tokyo Institute of Technology, O-okayama, Meguro-ku, Tokyo 152-8552, Japan 10.3762/bjoc.14.44 Abstract The catalytic asymmetric methylation of

• fluoroalkylated pyruvates is shown with dimethylzinc as a methylating reagent in the presence of a copper catalyst bearing a chiral phosphine ligand. This is the first catalytic asymmetric methylation to synthesize various α-fluoroalkylated tertiary alcohols with CF3, CF2H, CF2Br, and n-CnF2n+1 (n = 2, 3, 8

• copper. Keywords: asymmetric methylation; chiral phosphine ligand; copper catalyst; dimethylzinc; trifluoropyruvate; Introduction The introduction of fluorine atoms into organic compounds plays an important role in the discovery of lead candidates with unique biological and physicochemical properties

Non-cross-linked polystyrene-supported 2-imidazolidinone chiral auxiliary: synthesis and application in asymmetric alkylation reactions

• Quynh Pham Bao Nguyen and
• Taek Hyeon Kim

Beilstein J. Org. Chem. 2013, 9, 2113–2119, doi:10.3762/bjoc.9.248

• investigated. As shown in Table 3, benzyl bromide, allyl iodide and methyl iodide reacted very well to give the alkylated products 7 in moderate to good yields and excellent de values of >99% (Supporting Information File 1). Especially, the diastereocontrol of asymmetric methylation in this case was better

• acids 8a, 8b, and 8c in excellent ee values (Table 4, entries 1–3). To our surprise, although the asymmetric methylation proceeded very well with excellent diastereocontrol (>99 de), epimerization occurred under NaOH cleavage condition. Consequently, chiral acid 8d was obtained in only 89% ee (Table 4