title: Stereoselective Lewis acid mediated (3+2) cycloadditions of N-H- and N-sulfonylaziridines with heterocumulenes.
abstract: Alkyl and aryl isothiocyanates and carbodiimides are effective substrates in (3+2) cycloadditions with N-sulfonyl-2-substituted aziridines and 2-phenylaziridine for the synthesis of iminothiazolidines and iminoimidazolidines. Additionally, the stereoselective (3+2) cycloaddition of N-H- and N-sulfonylaziridines with isothiocyanates can be accomplished, allowing for the synthesis of highly enantioenriched iminothiazolidines. Evidence for an intimate ion-pair mechanism is presented herein in the context of these chemo-, regio-, and diastereoselective transformations. The demonstrated ability to remove the sulfonyl group from the heterocyclic products displays the utility of these compounds for further derivatization and application.
authors.affiliation: Warren and Katharine Schlinger Laboratory for Chemistry and Chemical Engineering, Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 E California Blvd, MC 101-20, Pasadena, CA 91125 (USA).
authors.forename: Robert A
authors.initials: RA
authors.lastname: Craig
authors.forename: Nicholas R
authors.initials: NR
authors.lastname: O'Connor
authors.forename: Alexander F G
authors.initials: AF
authors.lastname: Goldberg
authors.forename: Brian M
authors.initials: BM
authors.lastname: Stoltz
mesh_terms: D001388:Aziridines / Q000737:chemistry*; D061565:Cycloaddition Reaction; D006859:Hydrogen / Q000737:chemistry; D048289:Imidazolidines / Q000138:chemical synthesis / Q000737:chemistry; D058116:Lewis Acids / Q000737:chemistry*; D009584:Nitrogen / Q000737:chemistry; D013237:Stereoisomerism; D053778:Thiazolidines / Q000138:chemical synthesis / Q000737:chemistry; D015032:Zinc / Q000737:chemistry
chemical_list: D001388:Aziridines; D048289:Imidazolidines; D058116:Lewis Acids; D053778:Thiazolidines; D006859:Hydrogen; D015032:Zinc; D009584:Nitrogen
keywords: Lewis acids; cycloadditions; heterocumulenes; heterocycles; stereoselectivity