title: Asymmetric total syntheses of megacerotonic acid and shimobashiric acid A.
abstract: The asymmetric total syntheses of the α-benzylidene-γ-butyrolactone natural products megacerotonic acid and shimobashiric acid A have been accomplished in nine and 11 steps, respectively, from simple, commercially available starting materials. The key step for each synthesis is the (arene)RuCl(monosulfonamide)-catalyzed dynamic kinetic resolution-asymmetric transfer hydrogenation (DKR-ATH) of racemic α,δ-diketo-β-aryl esters to establish the absolute stereochemistry. Intramolecular diastereoselective Dieckmann cyclization forms the lactone core, and ketone reduction/alcohol elimination installs the α-arylidene.
authors.affiliation: Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599, United States.
authors.forename: Scott W
authors.initials: SW
authors.lastname: Krabbe
authors.forename: Jeffrey S
authors.initials: JS
authors.lastname: Johnson
mesh_terms: D015107:4-Butyrolactone / Q000031:analogs & derivatives* / Q000138:chemical synthesis* / Q000737:chemistry; D001597:Benzylidene Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D001688:Biological Products / Q000138:chemical synthesis* / Q000737:chemistry*; D002384:Catalysis; D003500:Cyclization; D004952:Esters; D007659:Ketones / Q000737:chemistry*; D007700:Kinetics; D015394:Molecular Structure; D012428:Ruthenium / Q000737:chemistry
chemical_list: D001597:Benzylidene Compounds; D001688:Biological Products; D004952:Esters; D007659:Ketones; C000601232:megacerotonic acid; C000601233:shimobashiric acid A; D012428:Ruthenium; D015107:4-Butyrolactone