title: A diastereoselective, nucleophile-promoted aldol-lactonization of ketoacids leading to bicyclic-β-lactones.
abstract: An improved, tandem acid activation/aldol-lactonization process is described. This more practical protocol shortens reaction times for the construction of bicyclic β-lactones from ketoacids and implements the use of commercially available reagents p-toluenesulfonyl chloride (p-TsCl) as activator and 4-dimethylaminopyridine (4-DMAP) as nucleophilic promoter (Lewis base). Substrates with β-substituents, with respect to the carboxylic acid, consistently showed excellent levels of diastereoselectivity during the bis-cyclization event.
authors.affiliation: Department of Chemistry, Texas A&M University, P.O. Box 30012, College Station, Texas 77842-3012, USA.
authors.forename: Gang
authors.initials: G
authors.lastname: Liu
authors.forename: Morgan E
authors.initials: ME
authors.lastname: Shirley
authors.forename: Daniel
authors.initials: D
authors.lastname: Romo
mesh_terms: D001643:Bridged Bicyclo Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D003500:Cyclization; D007651:Keto Acids / Q000737:chemistry*; D007659:Ketones / Q000737:chemistry*; D007783:Lactones / Q000138:chemical synthesis* / Q000737:chemistry; D015394:Molecular Structure; D013237:Stereoisomerism
chemical_list: D001643:Bridged Bicyclo Compounds; D007651:Keto Acids; D007659:Ketones; D007783:Lactones