Transfer Hydrogenation of Flavanones and ortho‐Hydroxychalcones to 1, 3‐Diarylpropanols Catalyzed by CNN Pincer Ruthenium Complexes. Issue 9 (26th February 2021)

• Record Type: Journal Article
• Authors: Soto, Martín; Gotor‐Fernández, Vicente; Rodríguez‐Solla, Humberto; Baratta, Walter
• Is Part Of: ChemCatChem. Volume 13:Issue 9(2021)
• Page Start: 2152
• Page End: 2157
• Publication Date: 2021-02-26
• Subjects: alcohols -- flavonoid -- transfer hydrogenation -- ketones -- ruthenium; Catalysis -- Periodicals; 541.39505
• DOI: 10.1002/cctc.202002025
• Languages: English
• ISSNs: 1867-3880

Abstract

Abstract: 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 NaO i Pr 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 . Abstract : Feeling the pinch : Efficient reduction of flavanones and 2'‐hydroxychalcones to 1, 3‐diarylpropanols has been achieved with the pincer ruthenium catalysts RuCl(CNN)(diphosphine) with NaO i Pr in 2‐propanol via transfer hydrogenation. The amount of base has been found to be a crucial parameter for the selectivity of this reactions. Preliminary results show that with chiral pincer catalysts, flavanone is reduced with 92 % of ee