title: Cation control of diastereoselectivity in iridium-catalyzed allylic substitutions. Formation of enantioenriched tertiary alcohols and thioethers by allylation of 5H-oxazol-4-ones and 5H-thiazol-4-ones.
abstract: We report highly diastereo- and enantioselective allylations of substituted 5H-oxazol-4-ones and 5H-thiazol-4-ones catalyzed by a metallacyclic iridium complex. Enantioselective Ir-catalyzed allylation of substituted 5H-oxazol-4-ones occurs with high diastereoselectivity by employing the corresponding zinc enolates; enantioselective Ir-catalyzed allylation of substituted 5H-thiazol-4-ones occurs with the corresponding magnesium enolates with high diastereoselectivity. The allylation of substituted 5H-oxazol-4-ones provides rapid access to enantioenriched tertiary α-hydroxy acid derivatives unavailable through Mo-catalyzed allylic substitution. The allylation of substituted 5H-thiazol-4-ones provides a novel method to synthesize enantioenriched tertiary thiols and thioethers. The observed cation effect implies a novel method to control the diastereoselectivity in Ir-catalyzed allylic substitution.
authors.affiliation: Department of Chemistry, University of California , Berkeley, California 94720, United States.
authors.forename: Wenyong
authors.initials: W
authors.lastname: Chen
authors.forename: John F
authors.initials: JF
authors.lastname: Hartwig
mesh_terms: D000438:Alcohols / Q000138:chemical synthesis / Q000737:chemistry*; D000498:Allyl Compounds / Q000737:chemistry*; D002412:Cations; D056831:Coordination Complexes / Q000737:chemistry; D003500:Cyclization; D007495:Iridium / Q000737:chemistry*; D015394:Molecular Structure; D010081:Oxazolone / Q000737:chemistry*; D013237:Stereoisomerism; D013440:Sulfides / Q000138:chemical synthesis / Q000737:chemistry*; D013844:Thiazoles / Q000737:chemistry*; D020002:tert-Butyl Alcohol / Q000138:chemical synthesis / Q000737:chemistry
chemical_list: D000438:Alcohols; D000498:Allyl Compounds; D002412:Cations; D056831:Coordination Complexes; D013440:Sulfides; D013844:Thiazoles; D010081:Oxazolone; D007495:Iridium; D020002:tert-Butyl Alcohol