title: Synthesis of 2,6-disubstituted dihydropyrans via an efficient BiBr(3)-initiated three component, one-pot cascade.
abstract: The rapid synthesis of cis-2,6-disubstituted dihydropyrans is achieved in a three-component, one-pot cascade reaction. BiBr(3)-ediated addition of ketene silyl acetals or silyl enol ethers to beta,gamma-unsaturated cis-4-trimethylsilyl-3-butenal provides a Mukaiyama aldol adduct containing a vinylsilane moiety tethered to a silyl ether. Addition of a second aldehyde initiates a domino sequence involving intermolecular addition followed by an intramolecular silyl-modified Sakurai (ISMS) reaction. Isolated yields of this one-pot reaction vary from 44 to 80% and all compounds were isolated as the cis-diastereomers (10 examples).
authors.affiliation: Department of Chemistry, the College of William & Mary, P. O. Box 8795, Williamsburg, VA 23187-8795, USA.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Hinkle
authors.forename: Yajing
authors.initials: Y
authors.lastname: Lian
authors.forename: Lee C
authors.initials: LC
authors.lastname: Speight
authors.forename: Heather E
authors.initials: HE
authors.lastname: Stevenson
authors.forename: Melissa M
authors.initials: MM
authors.lastname: Sprachman
authors.forename: Lauren A
authors.initials: LA
authors.lastname: Katkish
authors.forename: M Christa
authors.initials: MC
authors.lastname: Mattern