Stereoselective synthesis of (3R,4S,5S,9S)-3,5,9-trihydroxy-4-methylundecanoic acid δ-lactone
摘要:
A stereoselective synthesis of the pentaketide lactone (3R,4S,5S,9S)-3,5,9-trihydroxy-4-methylundecanoic acid delta-lactone has been achieved. (c) 2006 Published by Elsevier Ltd.
Asymmetric Hydrogenation of Alkynyl Ketones with the η6-Arene/TsDPEN–Ruthenium(II) Catalyst
摘要:
Enantioselective hydrogenation of alkynyl ketones catalyzed by Ru(OTf)(TsDPEN)(eta(6)-p-cymene) (TsDPEN = N-(p-toluenesulfonyl)-1,2-diphenylethylenediamine) affords the propargylic alcohols in up to 97% ee. The alkynyl moieties are left intact In most cases. The reaction can be conducted with a substrate-to-catalyst molar ratio as high as 5000 under 10 atm of H-2. The mode of enantioselection is elucidated with the transition state models directed by the CH/pi attractive interaction between the substrate and the catalytic species.