Reusable and highly enantioselective water-soluble Ru(II)-Amm-Pheox catalyst for intramolecular cyclopropanation of diazo compounds

• Hamada S. A. Mandour,
• Yoko Nakagawa,
• Masaya Tone,
• Hayato Inoue,
• Nansalmaa Otog,
• Ikuhide Fujisawa,
• Soda Chanthamath and
• Seiji Iwasa

Beilstein J. Org. Chem. 2019, 15, 357–363, doi:10.3762/bjoc.15.31

• diazoamide; Ru(II)-Pheox; water-soluble catalyst; Weinreb amide; Introduction Water-soluble transition metal complexes have been attracting increasing interest for catalytic applications because of their many advantages such as simple product separation, low cost, safety, and environmentally friendly

• previous work, we developed Ru(II)-Pheox catalysts for the intramolecular cyclopropanation of trans-allylic diazoacetates in a biphasic medium [29][30][31]. During the course of our continuous study on the development of a series of Ru(II)-Pheox catalysts, we found the introduction of an ammonium group on

• the aromatic ring connected with Ru gave high solubility in the water phase compared to a normal Ru(II)-Pheox complex as shown below (Figure 1) [32][33]. Then, Ru(II)-Amm-Pheox (cat. 2) was found to be soluble in water but not in diethyl ether. This fact prompted us to explore the asymmetric