Highly Z-Selective Julia–Kocienski Olefination Using N-Sulfonylimines and Its Mechanistic Insights from DFT Calculations

Takuma Chizaki, Koichi Fujiwara, Junko Fujimoto, Tetsuo Narumi, Satoshi Shuto, and Mizuki Watanabe

Org. Lett. 2025, XXXX, XXX, XXX-XXX.

The Julia−Kocienski (JK) olefination is effective for E-selective olefination, but highly Z-selective versions remain rare. Here, we report a highly Z-selective JK olefination (Z ratio >99:1) using N-sulfonylimines as electrophiles instead of aldehydes. This method demonstrates a broad substrate scope, tolerating electron-donating and-withdrawing groups, amides, halogens, carboxylic acids, and hydroxyls. Z-selectivity in our system arises from both the 1,2-addition and Smiles rearrangement steps without involving synperiplanar elimination. This study expands the toolkit for Z-selective olefin synthesis.

An amide-to-chloroalkene substitution improves the peptide permeability

Sayuri Takeo, Chihiro Iio, Ai Sakakibara, Mio Takeda, Yuki Yamazaki, Kohei Sato, Nobuyuki Mase, Mizuki Watanabe, Tetsuo Narumi

Chem Rxiv, 2024. DOI: 10.26434/chemrxiv-2024-l36zv

This study highlights the novel application of Chloroalkene Dipeptide Isosteres (CADIs) in enhancing peptide membrane permeability. Replacing the peptide bond with CADIs in model dipeptides significantly improved passive permeability. This enhancement is attributed to the increased lipophilicity provided by the CADI substitution, as confirmed by AlogP calculations and HPLC retention times. Molecular dynamics simulations further indicated that CADI substitution reduces water interaction, potentially lowering hydration energy. Our findings demonstrate that CADI incorporation can effectively improve the permeability of peptides, offering a valuable approach for developing bioactive peptidomimetics with enhanced pharmacological properties including permeability and hydrolytic stability.

Identification of Peptide-Based Hepatitis B Virus Capsid Inhibitors Based on the Viral Core Protein

Junko Fujimoto, Kazutoshi Kawahara, Kazuma Takeda, Sayuri Takeo, Kohei Sato, Kenji Nakashima, Nobuyuki Mase, Masaru Yokoyama, Tetsuro Suzuki, Tetsuo Narumi 

Bioorg. Med. Chem. Lett. 2025, 117, 130054.

In this study, we have identified two novel peptides, 19Ac (comprising residues 91-105) and 20Ac (encompassing residues 96-110), from a systematically designed peptide library based on the Hepatitis B virus (HBV) core protein, that inhibit the assembly of HBV capsid. Peptide 20Ac exhibited about twofold the inhibitory potency of 19Ac and proved effective against both standard and morphothiadin (GLS4)-resistant HBV strains. Molecular dynamics simulations revealed that despite their overlapping sequence, 19Ac and 20Ac bonded to different regions of the core protein, thereby inhibiting capsid assembly through distinct mechanisms. These peptides could serve as valuable seed compounds for the further development of HBV capsid inhibitors, including GLS4-resistant strains.