title: Isothiourea-catalyzed asymmetric synthesis of β-lactams and β-amino esters from arylacetic acid derivatives and N-sulfonylaldimines.
abstract: The isothiourea HBTM-2.1 (5 mol %) catalyzes the asymmetric formal [2 + 2] cycloaddition of both arylacetic acids (following activation with tosyl chloride) and preformed 2-arylacetic anhydrides with N-sulfonylaldimines, generating stereodefined 2,3-diaryl-β-amino esters (after ring-opening) and 3,4-diaryl-anti-β-lactams, respectively, with high diastereocontrol (up to >95:5 dr) and good to excellent enantiocontrol. Deprotection of the N-tosyl substituent within the β-lactam framework was possible without racemization by treatment with SmI2.
authors.affiliation: EaStCHEM, School of Chemistry, University of St Andrews , North Haugh, St Andrews KY16 9ST, U.K.
authors.forename: Siobhan R
authors.initials: SR
authors.lastname: Smith
authors.forename: James
authors.initials: J
authors.lastname: Douglas
authors.forename: Hugues
authors.initials: H
authors.lastname: Prevet
authors.forename: Peter
authors.initials: P
authors.lastname: Shapland
authors.forename: Alexandra M Z
authors.initials: AM
authors.lastname: Slawin
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Smith
mesh_terms: D000085:Acetates / Q000737:chemistry*; D002384:Catalysis; D061565:Cycloaddition Reaction; D004952:Esters; D007097:Imines / Q000737:chemistry*; D015394:Molecular Structure; D013450:Sulfones / Q000737:chemistry*; D013890:Thiourea / Q000737:chemistry*; D047090:beta-Lactams / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D000085:Acetates; D004952:Esters; D007097:Imines; D013450:Sulfones; D047090:beta-Lactams; D013890:Thiourea