Kinetic resolution of racemic planar-chiral vinylcymantrenes by molybdenum-catalyzed asymmetric metathesis dimerization

• Haruna Imazu,
• Hitoshi Izu,
• Yasuhiro Ohki and
• Masamichi Ogasawara

Beilstein J. Org. Chem. 2026, 22, 568–574, doi:10.3762/bjoc.22.42

• chiral-2a/meso-2a = 96:4 molar ratio, and the selectivity factor (krel) was calculated to be 754 based on a second-order equation. In all the three substrates examined, the dimerized products, chiral-2, were obtained in >98% ee thanks to the outstanding enantioselectivity. Keywords: cymantrene; kinetic

• in Figure 2) likely inhibits the effective interaction of the substrate with the chiral catalyst, resulting in highly enantioselective kinetic resolution. Cymantrene is far less electron-poor than ferrocene due to the presence of the three carbonyl ligands, which are strong π-acids, on the manganese

• (I). Indeed, the Friedel–Crafts acetylation of cymantrene, a typical electrophilic aromatic substitution reaction, is much slower than that of ferrocene. Consequently, vinylcymantrenes are electron-deficient olefins and less reactive in olefin metathesis. For this reason, the present AMD/KR reactions

Dimerization of a cell-penetrating peptide leads to enhanced cellular uptake and drug delivery

• Jan Hoyer,
• Ulrich Schatzschneider,
• Michaela Schulz-Siegmund and
• Ines Neundorf

Beilstein J. Org. Chem. 2012, 8, 1788–1797, doi:10.3762/bjoc.8.204

• (cymantrene) complexes to tumor cell lines, inducing high cellular toxicity. In order to increase the potential of the organometallic complexes to kill tumor cells, we were looking for a way to enhance cellular uptake. Therefore, we designed a branched dimeric variant of sC18, (sC18)2, which was shown to have

• the specific cell type. Finally, we could show that conjugation of a functionalized cymantrene with (sC18)2 leads to significant reduction of its IC50 value in tumor cells compared to the respective sC18 conjugate, proving that dimerization is a useful method to increase the drug-delivery potential of

• -homing agent, which accumulates in hypoxic tissue [10]. Furthermore, we reported on the delivery of functionalized cyclopentadienyl manganese tricarbonyl (cymantrene) complexes with the help of sC18, which lead to significant induction of cytotoxicity in tumor cells [11][12][13], which was even more