4) 重水素創薬を拡充する重アルキル化剤
澤間 善成、阪 一穂
和光純薬時報, Vol.94, No.2, 2026年4月
3) 重医薬品開発を指向した位置選択的重水素化法
澤間 善成
有機合成化学協会誌, 2026年1月号, p.50-61
2) Controlled formation of versatile methylated compounds based on ring opening of 4-methyl-1-siloxy-1,4-epoxy-1,4-dihydrobenzene
Takaaki Aijima,‡ Jin Tokunaga,‡ Sota Yoshimura, Yuki Itabashi, Tsunayoshi Takehara, Takeyuki Suzuki, Shuji Akai, Yoshinari Sawama
(‡equally contributed)
RSC Adv. 2026, 16, 15586–15590.
DOI: 10.1039/D6RA01853J
Abstract: We report an FeCl3-catalyzed transformation of 4-methyl-1-siloxy-1,4-epoxy-1,4-dihydrobenzene. Reaction in toluene gave the phenol product, whereas the addition of i-PrOH in 1,2-dichloroethane induced desilylative ring opening to produce 4-hydroxy-4-methyl-2,4-cyclohexadienone, which subsequently underwent a CO2Me-induced regioselective 1,2-methyl shift (C4 to C3) to afford 6-methyl-2,4-cyclohexadienone. This product bears a methyl-substituted quaternary carbon center that is difficult to access by existing methods and serves as a versatile intermediate for further structural elaboration. These results highlight a new mode of skeletal rearrangement and demonstrate regioselective control over competing reaction pathways.
1) Synthetic Studies Toward Rubioncolin B
Takaaki Aijima, Shuji Akai, Yoshinari Sawama
Eur. J. Org. Chem. 2026, 29, e202501103.
DOI: 10.1002/ejoc.202501103
Abstract: Herein, we report our synthetic studies toward rubioncolin B (1), a heptacyclic naphthohydroquinone dimer with antitumor activity. Our strategy is based on the intermolecular [4 + 2]-cycloaddition reaction between an ortho-naphthoquinone methide (o-NQM), which is generated in situ from a 1-naphthol derivative under catalytic Lewis acid conditions, and a naphthofuran derivative, thereby enabling the construction of a hexacyclic compound. We then explored three synthetic approaches for appending the remaining ring structure to the hexacyclic compound. Among them, the sequence involving the introduction of a Wittig reagent and subsequent cyclization proved effective, furnishing a cyclic acetal with the same ring structure as 1. This strategy not only demonstrates that accessing the highly congested architecture of 1 is feasible but also provides a versatile platform for the synthesis of structurally diverse analogs, thereby facilitating subsequent biological investigations, including structure–activity relationship studies.