title: Bi(OTf)3-, TfOH-, and TMSOTf-mediated, one-pot epoxide rearrangement, addition, and intramolecular silyl-modified Sakurai (ISMS) cascade toward dihydropyrans: comparison of catalysts and role of Bi(OTf)3.
abstract: Catalytic quantities of bismuth(III) triflate efficiently initiate the rearrangement of epoxides to aldehydes, which subsequently react with (Z)-δ-hydroxyalkenylsilanes to afford 2,6-disubstituted 3,6-dihydro-2H-pyrans. Isolated yields of desired products using Bi(OTf)(3) were compared with yields obtained when the reactions were run with TfOH and TMSOTf in the presence and absence of several additives. These studies, as well as NMR spectroscopic analyses, indicate an initial Lewis acid/base interaction between Bi(OTf)(3) and substrates providing TfOH in situ.
authors.affiliation: Department of Chemistry, The College of William & Mary, Williamsburg, Virginia 23187-8795, USA.
authors.forename: R Frederick
authors.initials: RF
authors.lastname: Lambert
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Hinkle
authors.forename: Stephen E
authors.initials: SE
authors.lastname: Ammann
authors.forename: Yajing
authors.initials: Y
authors.lastname: Lian
authors.forename: Jia
authors.initials: J
authors.lastname: Liu
authors.forename: Shane E
authors.initials: SE
authors.lastname: Lewis
authors.forename: Robert D
authors.initials: RD
authors.lastname: Pike
mesh_terms: D002384:Catalysis; D004852:Epoxy Compounds / Q000737:chemistry*; D058116:Lewis Acids / Q000737:chemistry; D058115:Lewis Bases / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D008698:Mesylates / Q000737:chemistry*; D015394:Molecular Structure; D011714:Pyrans / Q000737:chemistry*; D012821:Silanes / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D004852:Epoxy Compounds; D058116:Lewis Acids; D058115:Lewis Bases; D008698:Mesylates; D011714:Pyrans; D012821:Silanes; C445789:Bi(OTf)3