Synthesis of anti‐1,3‐Diols through RuCl₃/PPh₃‐Mediated Hydrogenation of β‐Hydroxy Ketones: An Alternative to Organoboron Reagents

Abstract

Hydrogenation of enantioenriched β‐hydroxy ketones promoted by the catalyst generated in situ from commercially available and inexpensive RuCl3 and PPh3 under hydrogen pressure allowed the efficient preparation of a variety of anti‐1,3‐diols in good yields and with a high level of diastereoselectivity. This method should be an interesting alternative to organoboron reagents for the diastereoselective reduction of β‐hydroxy ketones. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

Synthesis of Thelepamide via Catalyst-Controlled 1,4-Addition of Cysteine Derivatives and Structure Revision of Thelepamide

“…The first synthetic route commenced with a Ru-catalyzed reduction of β-ketoester 3 followed by Weinreb amide formation to afford β-hydroxyamide 4 in 70% yield over two steps and 99% ee (Scheme ). This material was subjected to ethylmagnesium bromide in Et 2 O at 0 °C to give hydroxy ketone 5 in 64% yield .…”

Application of chiral 2-isoxazoline for the synthesis of syn-1,3-diol analogs

“…NMR spectra of 8 – 10 exhibited only one set of signals corresponding to the syn -dihydroxy products, indicating an extra high diastereoselectivity ( syn : anti >99:1) during the reduction. To unambiguously determine the diastereomeric ratio, the anti -1,3-diol corresponding to 10 was prepared from 7 by RuCl 3 –PPh 3 -catalyzed hydrogenation [63–64]. However, the two diastereomers had identical proton NMR spectra.…”

Total Synthesis of the Phenolic Glycolipid Mycoside B and the Glycosylated p‐Hydroxybenzoic Acid Methyl Ester HBAD‐I, Virulence Markers of Mycobacterium tuberculosis

“…[27] Initially we applied the method reported recently by Phansavath and co-workers by diastereoselective hydrogenation with catalytic RuCl 3 and PPh 3 . [28] Although this provided the desired anti-diol, it also unfortunately resulted in concomitant reduction of the triple bond. Fortunately, the methodology of Evans and Chapman using NH 4 BH-(OAc) 3 gave 22 in good yield.…”