title: Cascading radical cyclization of bis-vinyl ethers: mechanistic investigation reveals a 5-exo/3-exo/retro-3-exo/5-exo pathway.
abstract: We recently described an iterative synthesis of oligo-vinyl ethers, followed by a radical cascade to provide a family of hexahydro-2H-furo[3,4-b]pyrans. Our results for the radical cascade were consistent with either a direct 6-endo-trig addition of a vinyl radical onto the first vinyl ether function or an initial 5-exo-trig addition, followed by rearrangement to the more stable anomeric radical intermediate. In this report, we describe our further mechanistic studies aimed at distinguishing between these two possibilities and conclude that the 5-exo/3-exo/retro-3-exo pathway is dominant.
authors.affiliation: Department of Chemistry, University of Victoria, Victoria, British Columbia, Canada V8W 3V6.
authors.forename: Natasha F
authors.initials: NF
authors.lastname: O'Rourke
authors.forename: Katherine A
authors.initials: KA
authors.lastname: Davies
authors.forename: Jeremy E
authors.initials: JE
authors.lastname: Wulff
mesh_terms: D003500:Cyclization; D005609:Free Radicals / Q000737:chemistry*; D005663:Furans / Q000737:chemistry*; D015394:Molecular Structure; D011714:Pyrans / Q000737:chemistry*; D013237:Stereoisomerism; D014753:Vinyl Compounds / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D005609:Free Radicals; D005663:Furans; D011714:Pyrans; D014753:Vinyl Compounds; C100195:vinyl ether