Asymmetric epoxidation under phase-transfer catalytic

Hori, K., Tamura, M., Tani, K., Nishiwaki, N., Ariga, M. and Tohda, Y. Asymmetric Epoxidation Catalyzed by Novel Azacrown Ether-type Chiral Quaternary Ammonium Salts under Phase-transfer Catalytic Conditions. Tetrahedron Lett. 2006, 47, 3115-3118. [Pg.33]

ASYMMETRIC EPOXIDATION CATALYZED BY NOVEL AZACROWN ETHER-TYPE CHIRAL QUATERNARY AMMONIUM SALTS UNDER PHASE-TRANSFER CATALYTIC CONDITIONS... [Pg.228]

S. Arai, M. Oku, M. Miura, T. Shioiri, Catalytic Asymmetric Epoxidation of Naphthoquinone Derivatives under Phase-Transfer Catalyzed Conditions , Synlett, 1998,1201-1202. [Pg.142]

SCHEME 48. Catalytic asymmetric epoxidation of naphthoquinone derivatives under phase transfer catalyzed conditions... [Pg.372]

Quaternary ammonium salts of alkaloids have been used for the synthesis of optically active oxiranes from electron-poor olefins under phase-transfer conditions. The enantiomer yield is inversely proportional to the dielectric constant of the solvent,Asymmetric epoxidation in the presence of catalytic amounts of poly-(S)-amino-acids in a triphase system has been described with optical yields up to 96% ... [Pg.28]

In 2007, the Lygo group surveyed the optimal oxidant for the asymmetric Weitz-Scheffer epoxidation of chalcone 50 through use of various oxidants in the presence of catalyst 8p. Among the oxidants, they found that aqueous sodium hypochlorite was the most effective oxidant for the epoxidations under mild phase-transfer catalytic conditions (Scheme 16.38). ... [Pg.125]