75848-98-5Relevant academic research and scientific papers
Transfer Hydrogenation of Flavanones and ortho-Hydroxychalcones to 1,3-Diarylpropanols Catalyzed by CNN Pincer Ruthenium Complexes
Soto, Martín,Gotor-Fernández, Vicente,Rodríguez-Solla, Humberto,Baratta, Walter
, p. 2152 - 2157 (2021)
The transfer hydrogenation of flavanones and ortho-hydroxychalcones catalyzed by ruthenium pincer complexes RuCl(CNNPh)(disphosphine) has allowed the synthesis of ortho-hydroxy 1,3-diarypropanols in 80–88 % yield, under mild reaction conditions and short reaction times (1 h) in 2-propanol. The amount of the co-catalyst NaOiPr has been found crucial for the selective reduction of flavanones to ortho-hydroxy 1,3-diarypropanols vs. flavan-4-ols. Preliminary results show that with pincer catalysts bearing (S,R)-Josiphos, flavanone is reduced to the corresponding (S)-alcohol in moderate conversion (36 %) and up to 92 % ee.
Intramolecular Alkylation of Phenols. Part 5. A Regiospecific Anionic Ring Closure of Phenols via Quinone Methides
Murphy, William S.,Wattanasin, Sompong
, p. 1567 - 1577 (2007/10/02)
The bis-magnesium salts of the triols (6a) and (6h) cyclise when heated in benzene with high ortho-regiospecificity to the corresponding bis-phenols (7) and (8).The triols (6k) and (6o) under the same conditions cyclise with high para-regiospecificity to the corresponding bis-phenols (7) and (8).Both (6a) and (6h) cyclise via o-quinone methides, and (6k) and (6o) via p-quinone methides.Results from the use of, inter alia, 18-crown-6, indicate that the high ortho-regiospecificity of the cyclisation of (6a) and (6h) is due to intramolecular Mg(II) bridging of the intermediate o-quinone methides.The high para-regiospecificity of cyclisation of (6k) and (6o) is due to steric hindrance towards o-cyclisation of the intermediate p-quinone methides presented by the Mg(II) cation.The unexpected facility with which (6a) and (6k) undergo ring closure is discussed.
